Pull in @cunei's suggestion for a more complete Ivy->Maven dynamic revision convertor.

   We attempt to convert these constructs to maven:
   * 1.+
   * ]1,2]
   * [2,3[
   * 1+  - Albeit this one is a heuristic for accuracy.

This should help ivy users which prefer the nicer 1.2.+ syntax.

Also adds tests/improves exisitng tests.