Revert "Preparing to Remove Mt. Gox"

This reverts commit 3f37cb9ad0236549d9da0c625bf7b108c6754867.
Revert 3f37cb9..151ee2b

This rolls back to commit 3f37cb9ad0236549d9da0c625bf7b108c6754867.
Began work on new message protocol.

After looking over the code I’ve decided that the messaging protocol is
too rigid and have designed a new, hopefully more modular, protocol.
This should make it easier to add and remove Bitcoin exchanges in the
future. It should also allow the user to only display desired exchanges.