Revert "`cf start` command now only makes a stats request, not stats+instance"

This reverts commit 07d9dab07727dca372d874c415945f564b42d7b0.
Revert "Added API method and test for getting app stats independently"

This reverts commit 87702edd90c3de3d3fd61c9680a6b19b6fc8ec75.