Remove GCC 'initialized variables' warning flag in favor of LLVM warning for same

- Wuninitialized required Optimized flag (O) and optimizations made debugging and testing frustrating.
LLVM warnings for initialized vars are turned on by default so we are not losing any compiler help by
doing this assuming use of "modern" development environment (i.e. Xcode 4 / 5, clang, etc)
Add Cedar specs target and PivotalCoreKit to support testing
update default config name for specs
Add asynchronous means of mapbox source creation.
Merge branch 'tests' of github.com:boundsj/mapbox-ios-sdk into tests

Conflicts:
	MapView/MapView.xcodeproj/project.pbxproj
	MapView/Specs/Specs-Prefix.pch