Fix analyzer warnings

GL bindings for "GL_KHR_blend_equation" and "GL_KHR_debug"

Renamed AnimatedType to AnimatedValue

Updates sprite widget to handle changes to renderbox

Minor style changes around demo cards.

Make typography.white and typography.black constants.

Rename sky_packager to sky_snapshot

This program just creates a snapshot, not the whole package.

Dismissable: animate "snap back", only call dismiss() once

This demo is a fuzzer of sorts, testing in particular our text layout system and painting

Use didMount(), didUnmount() to manage the VariableHeightScrollable layoutState listener.

Fix dart_pkg.py build crash

We need to work in absolute paths because os.path.exists("foo/..") is False but
os.mkdirs("foo/..") will generate an error.

Try to clarify initial execution.

Increase j to 4

Fix typos in RenderImage

Try building faster on Travis now that we're using Release and have less code.

This function took innerConstraints as an argument but used constraints internally.

sky/engine and sky/services updates for Mac target

Build configuration and toolchain updates for iOS and Mac targets