Log Message:
Changes 0.12.2:
Add extern "C" guards to the public headers for C++ compatibility
Improvements to style override API and implementation
Bugfixes:
* Fix some rasterizer bugs of unknown severity
* Fix a broken memset() of unknown severity
* Make timestamp parsing more lenient, which makes libass accept invalid files \ 
accepted by most other ASS parsers
* Increase compatibility with broken ASS drawings accepted by VSFilter