Restore previously removed methods to keep backwards compatability

The purpose of this PR is to allow us to include the reorganization from #64 in a minor version release. In a 3.0 release we might look into getting rid of these extra methods since they would be better off in the `request` object being passed in to `WPCOM`.
Revert commit 718e42ff0133793bbd46adbf142fdddee9eaa301.