Moved typedefs to enum definition in ct_internal.h

I moved the typedefs from the top of the code to where the actual enums
are defined in cuetext_internal.h as there was a problem where they
were not visible when including cuetext.c in the new unit tests.
Change cuetext parser to use const webvtt_byte *.
Added unit tests for internal cue text functions.

- Added cuetexttokenizer_testfixture which.
- Added unit tests for the data, escape, and tag tokenizer
functions.
Merge pull request #351 from RickEyre/tokenizer-tests

Tokenizer tests
Make cuetext_internal.h enums anonymous.
Merge pull request #352 from RickEyre/fix-typedefs

Make cuetext_internal.h enums anonymous.
Add regression test for bug 853879 test case
Set default file attributes to text with unix line endings
Print message if we fail to load file (To explain broken distcheck)
Add regression testdata to dist, fix leak in regression_testfixture
Update comment on RegressionTest.Bug853879

Comment has been made slightly more accurate.
Fix comment in data tokenizer unittest.
Merge pull request #355 from RickEyre/fix-comment

Fix comment in data tokenizer unittest.
Merge pull request #353 from caitp/issue-353

Add regression test against endless loop spotted in bug #853879