Added GenVersions generator.
Removed AppVersion and ScalaVersion from ScalaTestBundle.properties, and make AboutJDialog and Runner to use org.scalatest.version and org.scalatest.buildForScalaVersion instead.
Make scalactic sub-project to generate Versions.scala also.
Tweaked out ScalaTest an Scalactic versions are done. Dropped the buildForScalaVersion from the package objects,
changed "version" to "ScalacticVersion" and "ScalaTestVersion" in the package objects. (Made two instead of
one package object, because if someone gets a mismatch between Scalactic and ScalaTest version numbers, that
is more easy to see.)