Update to 0.9.25:

Overview of changes leading to 0.9.25
Wednesday, December 4, 2013
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- Myanmar shaper improvements.
- Avoid font fallback in CoreText backend.
- Additional OpenType language tag mappiongs.
- More aggressive shape-plan caching.
- Build with / require automake 1.13.
- Build with libtool 2.4.2.418 alpha to support ppc64le.

(wiz)