Require less current autotools so we build on MacOS.

I didn't review things particularly carefully, but I don't see
any features the build scripts are depending on from newer
autotools releases except for AM_SILENT_RULES which can be
handled with m4_ifdef.

In any case, this seems to work fine with the autoconf 2.61
and automake 1.10 supplied by XCode 4.5.2.
Mark failing tests as XFAILs instead of disabling them.

GTest has a mechanism for marking tests as disabled when
they're not ready. Automake has another method, where executables
can be marked as 'expected to fail'.

The gtest method has finer granularity, but the automake
method is more transparent about what's working and what's
not.

This commit enables everything but
CueIdLanguage.DISABLED_LongStringMultipleLanguages which hangs in
an inifinite loop. All of the unit tests are added to the XFAIL
list since none of them completely pass at this point.
Fixed seg fault cause by improper access of memory in read_cuetext() when checking for an ASCII_LF while length is 0. Modified the string_getline() function in order to retain the newline characters. This solved a problem when the parser needs to check for the newline characters in order to determine whether or not it is finished a cue.
Adding csposition_unittest to know valgrind failures.
Merge branch 'xfail-tests' of git://github.com/rillian/webvtt into bug-test
Fixed bug that was introduced in last bug fix where some parsing functions needed to retain the new line from webvtt_string_getline while others did not. Added in an option to specify whether or not you'd like the new line returned with the string in webvtt_string_getline.
Merge pull request #8 from rillian/mac-autotools

Require less current autotools so we build on MacOS.
Merge pull request #4 from rillian/dev-fixes

More 'distcheck' fixes
Merge pull request #13 from RickEyre/bug-fixes

Fixed seg fault cause by improper access of memory in read_cuetext() whe...
Shorten --enable-valgrind-testing to --enable-valgrind.

The former is too long.

Also removes a redundant check and combines the common valgrind
command line arguments. This adds --read-var-info=yes on MacOS.
It was disabled to work around a bug[1] but I don't see this issue
with valgrind 3.8.1, so I think it's safe to re-enable.

[1] http://comments.gmane.org/gmane.comp.debugging.valgrind.devel/2220