use unique_ptr for automatic deallocation
do not crash for missing images
use CoreImage for decoding/encoding images on osx/ios
fix gyp project
also allow underscores in token names
bump cocoa
use more modern libpng version instead of the system-provided one and fix compile errors
Merge branch 'master' into platform-image

Conflicts:
	gyp/install.gypi
use -lpthread instead of -pthread
fix image y reversal
use test suite as submodule instead of using npm
use binary mesa on travis to speed up build times
use nunicode for proper to_upper/to_lower string conversions
add <cstring> for std::memset
remove dependency on node
call correct image compare script
Merge pull request #531 from mapbox/remove-node

Remove dependency on node.js
Merge branch 'master' into platform-image
declare explicit MACOSX_DEPLOYMENT_TARGET - refs #529
bump cocoa bindings