Add support for JSON config files

If 'DB5.plist' is found, it will be used; otherwise 'DB5.json' will be
used.
singleton and podspec;
Merge commit '54f05a7299b1141bf44bc2b223b99a2d5c30bfde'
Removed unused properties and headers.
Moved theme loading out of -init to allow for dynamic reloading.
Added support for optional alpha in colorWithHexString().
Added URL support for theme loading.
Merge pull request #1 from wdn/master

Singleton, podspec and support for alpha in colors