Models Moving Plan

[David Edmundson]

All done!
(except for the newly discussed re-doing of Tp::ContactCapabilities..
but that can happen afterwards, it's not a regression.)

I officially propose model_refactor_2 branch for merging into master.

I'm not sure what the easiest way to review all this code is. Do
people want this on RB? It'd be one mega huge patch, which I imagine
is hard to look through (there are > 40 commits total).
Or we can look at the branch and comment in emails.

Please do help review it, even if you are a new developer.

Next steps are:
 - Review
 - Merge to master
 - Confirm which bugs it fixes.. and close them.

 - Port the plasmoids to these models
 - Remove the old models
 - Fix the roles enum (needs to sync with kpeople)