Add a check for db schema version

nipapd should refuse to start if the PostgreSQL db schema version is
outdated.

The up-to-date schema version (required to run) is stored inside
nipap/__init__.py
The current schema version is read out of the database comment.

The web-ui ( /version ) will also show the schema version.
cli: Don't use colon as delimiter in tab completion

Some strings (e.g. VRF) use a colon so this character should not be used
as a delimiter by bash completion
Merge pull request #567 from dosomder/cli/422-fix-tab-completion

cli: Don't use colon as delimiter in tab completion
Add support for Ubuntu 14.04

.. by having nipapd depend on postgresql-9.1-ip4r OR postgresql-9.3-ip4r
instead of just on the 9.1 package. Should perhaps also work on Debian
unstable (which seem to feature both postgresql-9.3 or 9.4).

Fixes #568.
Merge pull request #569 from plajjan/568-fix-postgres-depends

Add support for Ubuntu 14.04
Further improve CLI "colon" tab completion

This changes the way tab completion works with regards to colon.

Given we have VRFs 123:123 and 123:456. Before change would yield
$ nipap address add vrf_rt 123:<tab>
$ nipap address add vrf_rt 123:123\:
Which is clearly broken. However this works:
$ nipap address add vrf_rt 123\:<tab>
123:123 123:456

While after the change, we fix the first behaviour
$ nipap address add vrf_rt 123:<tab>
123 456
But the completion lists only the part right of the colon and not the
complete VRF RT, which could be perceived as incorrect.

Kind of part of #422.
Update NEWS file
Merge pull request #488 from dosomder/460-check-db-version

Add a check for db schema version