Added additional Maven profile for skipping known flaky tests

Use the Maven profile `skipFlakyTests` for not executing tests that are known
to be flaky. Inside Eclipse, you can achieve the same by passing the system
property `-DskipFlakyTests=true`.

This was done to preventing the Scala/IDE integration script to fail because of
flakiness in our regression suite.

Known flaky tests are re-executed up to 5 times (this is tunable).  The
``maySkipFlakyTest`` class is not the finest piece of logic, but it gets the
job done.