Rename addCacheProvider to withCacheProvider and remove the list implementation.
Merge branch '2.x' of https://github.com/allenxwang/ribbon into 2.x-ssl

Conflicts:
	build.gradle

More changes in proxy to use the Observable API for content.
Merge pull request #119 from allenxwang/2.x

Rename addCacheProvider to withCacheProvider and remove the list implementation
Merge branch '2.x' of https://github.com/Netflix/ribbon into 2.x-ssl