WIP

Arrays of Swift types won't compile. `TestModel.stringArray`
Remove flatten and try more things
Use switch for Swift 1.1 compatibility
Use JSON enum and function composition
Use if-let for data unwrapping
Fix PR comments
Use subscript with JSONValue
Fixed case sensitivity for file paths

The Xcode project file contained four cases where lowercase  characters
were incorrectly used in file paths.  This breaks on Mac OS Extended
(Case-sensitive, Journaled) filesystems.
Add OS X target

Rearranged the project a little bit and added an OS X target so that
this can be used for mac apps.
Merge remote-tracking branch 'origin/td-json-enum'
Merge remote-tracking branch 'origin/gf-osx-target'

Conflicts:
	Argo.xcodeproj/project.pbxproj
	ArgoTests/JSON/JSONFileReader.swift