Inprove dependencies and nomenclature

• Renaming CachedCall into Cached
• Make RequestBuilder and ResponseUtils inner classes of CachedCallAdapter
• Implemented new tests matching Retrofit.
• Sync calls now are also cached

Fix unnecessary cast

• Added clone() method to CachedCall interface to avoid unnecessary cast

Remove cached entry

Added the option for remove a cached entry

First Working Version

Added all required utils to set a cache to retrofit