Log Message:
Release 0.13.1:
Much faster duplicate event check in ass_process_chunk. This can bring a large \ 
speedup for embedded subtitles with lots of events. To make this possible, it is \ 
now forbidden to combine calls to ass_process_chunk with any other method of \ 
manipulating the event list, namely, manual manipulation and calls to \ 
ass_process_data, ass_read_memory and ass_read_file.
Interpret negative timestamp components as actual negative numbers. This change \ 
increases compatibility with VSFilter.
Font matching changes for VSFilter compatibility
Look up fonts that contain PostScript outlines by their PostScript name instead \ 
of their full names. Family names continue to be used for all fonts.
Keep spaces in font names
Drop support for Fontconfig < 2.10.92 to ensure correct font matching
Bug fixes
Fix building the assembler code for the x32 ABI
Fix static linking against libass through pkg-config when libass uses libiconv
Fix some small memory leaks, potential crashes and bad data uses