libusb.c: consolidate USB-related addvar() calls
Remove redundant usb_set_altinterface(), unless user requests it

Adds flag/value to USB driver options.

Closes networkupstools/nut#138
nut-usbinfo: ignore *.orig files
Also check for source-highlight at configure time

source-highlight is used for documentation generation. It's
however optional, so we just check for the sake of completion
Explicitly use subdir-objects in automake init

Closes networkupstools/nut#155
Don't reference subdir-object with $(top_srcdir)

Replace references to objects in separate directories that were
using $(top_srcdir) by the expanded version '../../'. The variable was
otherwise part of the path, resulting in build failures. This completes
commit f8abb9b

Closes networkupstools/nut#155
Clarify a bit more Avahi build requirements
docs: add NUT version number/date into footer of HTML pages

Reference: https://github.com/networkupstools/nut/issues/150
docs: move DocBook options common to html stylesheets to common.xsl
docs: add NUT version number/date in PDF documents

Reference: https://github.com/networkupstools/nut/issues/150
apcsmart: increase passes in setvar_enum()

Current 6 is not enough for bigger units - especially if we swap to the
value directly preceeding the current setting.

Signed-off-by: Michal Soltys <soltys@ziu.info>
drivers : fix possible memory leak.

In arguments parsing, if user option is passed.
drivers : add Liebert GXT3 device.
Merge branch 'issue_138_altinterface_value'

Removing the usb_set_altinterface() call seems to be a net positive, but there
is a new `usb_set_altinterface` driver option to restore the old behavior.
missing -lm in drivers/Makefile.am

Both bcmxcp and bcmxcp_usb use ldexp(), so both need `-lm`.

http://news.gmane.org/find-root.php?message_id=544515BA.4060804%40niksoggia.it
docs: docinfo.xml is now auto-generated
riello_ser: enhanced handling error codes (0.03)
riello_usb: timeouts and error handling (0.03)

Small changes in riello_usb.c that solved some problem with managing
transmission errors between the Raspberry Pi and Riello ups (thanks to Fredrik
Öberg): introducing timeout in reading ups data in cypress_command; enhanced
handling error codes

http://news.gmane.org/find-root.php?message_id=f5294e5579574bcbaf5cdd95523e0b68%40AM3PR07MB289.eurprd07.prod.outlook.com
riello_usb: explicitly claim USB interface

Reference: http://news.gmane.org/find-root.php?message_id=7731ed2f98014b8a90e695a06d077970%40AM3PR07MB289.eurprd07.prod.outlook.com

and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=738122
HCL: Rucelf UPOII-3000-96-EL supported by blazer_ser

Manufacturer: http://www.rucelf.ua/en/catalog/upoii-3000-96-el/

Closes: https://github.com/networkupstools/nut/issues/165