V.2.0 upgrades

Here is an attempt to fill inn the gaps of the upgrades from v.1.x to v.2.0.

Running alembic after applying these on a master installation, gave the following output:
https://gist.github.com/jalavik/66d909e00d12ee2be3fe

Most of it are not applicable, except maybe the column change in the `tag` table, but I am not sure if this one is necessary..

Touches #1613
Ah, OK, I assumed you were looking at part one (=checking whether all *master* tables and demosite fixtures have been well propagated to *next*) while you are already on part two (=preparing future v1->v2 migration).  Is part one already finished?  See #1613.