add support for ordered match sets

[abelhegedus]

Results of some brain storming with @ujhelyiz and @bergmanngabor :

• Reuse the existing OrderBy annotation for providing additional methods in matchers that return ordered sets based on a comparator parameterized with the given expression.
  • ISortedMatcher interface and BaseGeneratedSortedMatcher class
  • getAllMatchesSorted, getFirstMatch, getLastMatch, getComparator
• The sorting can be later pushed down to the RETE level
• Maybe include sorted delta monitors (found and lost matches with their indexes?

[ujhelyiz]

Use case: soft links.

[abelhegedus]

Moved to Eclipse.org BugZilla https://bugs.eclipse.org/bugs/show_bug.cgi?id=398768