Add tagging to release script.

I've tested most of this, except for the actual svn copy.  So this is all
commented out for now.  Two things to be aware of:

  1. The "user" variable needs to be changed.
  2. I'm not sure whether the quotes on the svn copy line will
     work properly.  Escaping quotes is always a tricky business.


git-svn-id: http://svn.code.sf.net/p/rosegarden/code/trunk/rosegarden@13219 cf6a83e7-f017-4305-b0b3-678bde24f230