Replace snapshots with a timestamp

[ebourg]

When building with Maven, if the property ${project.version} is used as the package version and the version is actually a snapshot (with a -SNAPSHOT suffix), Redline throws the following error:

An Ant BuildException has occured: java.lang.IllegalArgumentException: version with value: '1.0-SNAPSHOT' contains illegal character -

It would be nice to automatically replace the -SNAPSHOT suffix with a timestamp instead, jdeb does this when building .deb packages.