Ffsubsync

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* Add ability to merge synced and reference subs into bilingual subs when reference is srt;

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* Fix bug when handling ass/ssa input, this format should work now;

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* Better detection of text file encodings;
* ASS / SSA functionality (but currently untested);
* Allow serialize speech with --serialize-speech flag;
* Convenient --make-test-case flag to create test cases when filing sync-related bugs;
* Use utf-8 as default output encoding (instead of using same encoding as input);
* More robust test framework (integration tests!);

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* Try to correct for framerate differences by picking best framerate ratio;

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* Revert changes from 0.2.9 now that srt parses weird timestamps robustly;

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* Revert changes from 0.2.12 (caused regression on Windows);