Refactor, extract mel.cmd.rotomapedit.Controller
Refactor, extract mel.cmd.rotomapedit.Controller

Step towards untangling the mode logic in 'mel rotomap-edit' by
extracting all of it to a class.

Test Plan:
$ ./meta/run_tests.sh
.. Zoom around, follow, paste, move moles with rotomap-edit ..

aevri/mel,aevri/mel