"skip install" for lib Xcode targets for easier app archiving
pass png_static_libs to other_ldflags in install.gypi on Linux, closes #581
Merge pull request #600 from mapbox/png-other-ldflags

pass png_static_libs to other_ldflags in install.gypi on Linux
add note about access token & where to find Linux binary
Merge branch 'master' of github.com:mapbox/mapbox-gl-native
Update README.md
Remove rotation constraints

This should be an iOS SDK option, not hard coded into
low-level renderering.

Fixes #458
Fix OS X build
Merge branch 'master' into image-readers
image_readers: premultiply alpha