Autotools updates

Few autotools updates and de-duplication of the README file.
NOTE: not sure about the readme file if that works on windows this way.

Please remember to run "make distcheck" call to test and then release the source tarballs from the tag :)
To answer my own question, no it is not.
```
/usr/bin/docbook2man docs/openxcom.6.xml
Using catalogs: /usr/share/sgml/sgml-iso-entities-8879.1986/catalog, /usr/share/sgml/xml-iso-entities-8879.1986/catalog, /usr/share/sgml/docbook-sgml-3.1/catalog, /usr/share/sgml/docbook/dsssl-stylesheets-1.79/catalog, /usr/share/sgml/docbook/xml-dtd-4.4/catalog
Using stylesheet: /usr/share/sgml/docbook/utils-0.6.14/docbook-utils.dsl#print
Working on: /build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:13:0:E: URL not supported by this version
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:13:0:E: DTD did not contain element declaration for document type name
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:15:9:E: element "REFENTRY" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:17:14:E: element "REFENTRYINFO" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:18:10:E: element "ADDRESS" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:19:9:E: element "EMAIL" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:21:12:E: element "COPYRIGHT" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:22:8:E: element "YEAR" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:23:10:E: element "HOLDER" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:25:10:E: element "DATE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:28:9:E: element "REFMETA" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:29:16:E: element "REFENTRYTITLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:30:12:E: element "MANVOLNUM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:31:21:E: there is no attribute "CLASS"
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:31:29:E: element "REFMISCINFO" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:32:30:E: element "REFMISCINFO" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:35:12:E: element "REFNAMEDIV" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:36:10:E: element "REFNAME" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:37:13:E: element "REFPURPOSE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:42:16:E: element "REFSYNOPSISDIV" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:43:14:E: element "CMDSYNOPSIS" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:44:11:E: element "COMMAND" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:45:7:E: element "ARG" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:45:20:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:49:10:E: element "REFSECT1" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:50:8:E: element "TITLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:51:7:E: element "PARA" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:52:11:E: element "COMMAND" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:59:10:E: element "REFSECT1" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:60:8:E: element "TITLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:61:15:E: element "VARIABLELIST" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:62:16:E: element "VARLISTENTRY" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:63:9:E: element "TERM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:63:17:E: element "OPTION" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:63:45:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:64:13:E: element "LISTITEM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:65:9:E: element "PARA" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:66:21:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:70:16:E: element "VARLISTENTRY" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:71:9:E: element "TERM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:71:17:E: element "OPTION" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:71:45:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:72:13:E: element "LISTITEM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:73:9:E: element "PARA" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:74:21:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:78:16:E: element "VARLISTENTRY" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:79:9:E: element "TERM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:79:17:E: element "OPTION" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:79:31:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:79:71:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:80:13:E: element "LISTITEM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:81:9:E: element "PARA" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:82:28:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:82:62:E: element "REPLACEABLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:83:50:E: element "LITERAL" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:87:16:E: element "VARLISTENTRY" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:88:9:E: element "TERM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:88:17:E: element "OPTION" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:89:9:E: element "TERM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:89:17:E: element "OPTION" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:90:13:E: element "LISTITEM" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:91:9:E: element "PARA" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:98:10:E: element "REFSECT1" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:99:8:E: element "TITLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:100:7:E: element "PARA" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:104:10:E: element "REFSECT1" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:105:8:E: element "TITLE" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:106:7:E: element "PARA" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:107:14:E: there is no attribute "URL"
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:107:36:E: element "ULINK" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:108:62:E: element "ULINK" undefined
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:109:8:E: end tag for "ULINK" omitted, but its declaration does not permit this
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:108:3: start tag was here
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:109:8:E: end tag for "ULINK" omitted, but its declaration does not permit this
nsgmls:/build/openxcom-git/src/OpenXcom/docs/openxcom.6.xml:107:3: start tag was here
Unknown processing instruction: xml version='1.0' encoding='UTF-8'? at /usr/share/sgml/docbook/utils-0.6.14/helpers/docbook2man-spec.pl line 1241, <STDIN> line 1.
Makefile:7434: recipe for target 'openxcom.6' failed
make[1]: *** [openxcom.6] Error 8
make[1]: Leaving directory '/build/openxcom-git/src/OpenXcom'
Makefile:6960: recipe for target 'all-recursive' failed
make: *** [all-recursive] Error 1
```

Ew @ that.

Would it be better to switch to xmlto for manpage generation? Besides solving the non-standardized naming problem (I think), it has the advantage of being actively developed.

I've tested it by exporting DOCBOOK2MAN="/usr/bin/xmlto man" before ./configure, and I can see no problems with the resultant manpage. If anything, it looks better than the docbook2x generated manpage. [1]

[1] http://i.imgur.com/GGFQjLW.png