Wrapped #include <libwebvtt/lexer.cpp> in extern "C" block
Merge branch 'lex-newline' of git://github.com/rillian/webvtt into lex-newline-ril
Include <libwebvtt/lexer.c> after C++ headers in lexer_unittest.cpp
Merge pull request #297 from caitp/webvtt-lex-newline

Add `webvtt_lex_newline` func to read newlines in reentrant manner
Use quotes around the .c include in the lexer unit test.

This helps emphasize that it's a local C file we're including,
not a public header.