Fix bzr mirrors not updating  (must revisit --mirror option in #18)

Fixing problem with already existing tags

Conflicts:
	CHANGELOG.md
	docs/prerequisites.md
	lib/VERSION

Improved the SVN documentation and separated types of mirrors
into different sections.

Now adding different types of mirrors will be more managable.

and adding them to their own document for archival purposes.

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.