enhaced if and unless conditions

[GoogleCodeExporter]

Current if and unless conditions will to an string equality check between
the property specified and the expanded value.

Allow for other types of checking, like:
- regular expression match
- file path type glob (could be used for project base dir matching)
- numeric <, >, <=, >= (this would be good for priorities)

Original issue reported on code.google.com by [email protected] on 12 Mar 2009 at 1:17