Pause unpause

This is the rerecorded VCRs and minor updates for API Version v1.12.

Things changed:

1.   Added `Docker::Container#pause` and `Docker::Container#unpause` support thanks to @amuino
2.   Removed `Docker::Image#insert` support since this has been removed from the API altogether in favor of Dockerfile's `ADD`.

This should wait till after v1.12.0 is pushed.