Merge branch 'upstream-master' into 2.0-devel-zwaldowski
Bump min. deployment target to 6.0/10.8.
Fix missing headers in distribution
Move to XCTest.
Bake in configuration
Remove build scripts
Strip use of EXTScope.
Amend this to earlier
Replace EXTRuntimeExtensions with MTLPropertyAdditions.
Optimize using shared key dictionaries.
Fix screwup
Optimize storage behavior cache generation.
Reuse MTLPropertyAttributes instances
Simplify MTLSelectorWithKeyPattern
Make NSDictionary+MTLJSONKeyPath follow convention.
Amend to test move
Fix some general warnings
Remove now-defunct mtl_firstObject
Remove all deprecated implementations
Remove support for old NSCoding archives