SVN tags/branches not updated, closes #4

Adding ability to mirror tags in svn repository

It actually always worked I just set up the prerequisites
incorrectly.

I've made some improvements to bazaar repository support.
However, the support just isn't there yet.  I get
multiple errors.

Bazaar support is added.  Thanks @agb80! 

There's a couple of modifications to the preflight check which need to be done but I know what they are and can do that pretty quickly.

Some modifications were in order so that gitlab-mirrors
works with the latest pyapi-gitlab.