Release 0.11.0

• Add bitmap run combining/compositing
  This changes the text rendering model and increases compatibility with
  VSFilter. It may make rendering faster or slower in certain cases.
• Add AVX/SSE2 implementations for \be and compositing
  This adds yasm as (optional) build dependency.
• Add ass_library_version() API funcion (GC #113)
• Add 'profile' program for benchmarks
• Improve gaussian blur
• Fix compilation with MSVC 2013
• Speed up HarfBuzz shaper
• Speed up cache
• Notable compatibility bugfixes
  • Reset origin on \fay changes (GC #88)
  • Tons of parser fixes
  • Fix ascender/descender metrics (GH #8)
  • Fix \pbo sign and scaling
  • Don't reset wrap style on \r (GC #116, GH #45)
• Notable bugfixes:
  • Correctly handle @font advance (GC #94)
  • Disable ligatures for non-zero \fsp
  • Make sure to release vector clip (GH #22)