Description of problem:
Please add exclusion paths to the backup.  Both tar and rsync handle excludes. 
Here is a real world example:

I want to backup my /var/lib directories because they contain stateful
information, like my mysql databases.  However, I also use this system to build
for mock.  This currently uses 2.4G of space (cached build roots) - and since
they are cached, they are recreated whenever needed.

If I want to backup /var/lib/ and skip mock, I have to add:
+ /var/lib/a
+ /var/lib/b
+ /var/lib/c
+ /var/lib/d
etc

etc. to the backup set.

It would be much nicer to be able to add:
+ /var/lib
- /var/lib/mock

Version-Release number of selected component (if applicable):
fwbackups-1.43.0-0.1.beta2.fc6