Merge pull request #9 from mozilla-servo/brson

Update CompositionOp C bindings to fix tests
Add fontconfig to link line on linux.
Remove cairo fully, and fix early free bug in scaled_font creation.
Merge pull request #10 from metajack/linux-font-fixes

Linux font fixes
Fix error for non-exhaustive pattern match.

I missed this in the last round of removing Cairo stuff.
Merge pull request #11 from metajack/nonexhaustive-backends

Fix error for non-exhaustive pattern match.
Fix build warnings on mac and linux.
Merge pull request #12 from metajack/warning-police

Fix build warnings on mac and linux.
Only use -Wno-c++11-extensions when clang is detected
Disable error that forbids builds with gcc 4.2