Added a ``FlakyTest.retry`` combinator to be re-run tests known to be flacky

In our test suite we have a number of tests that are known to be flacky. The
``FlakyTest.retry`` combinator re-executes the same time up to N times (where
N is defaulted to 5 at the moment).

While we should of course strive to fix all sources of flackiness in tests, this
is a pragmatic solution to prevent spurious build failures.
Added Maven profile ``retryFlakyTests`` to reduce spurious test failures

Use the Maven profile ``retryFlakyTests`` for being robust against tests that
are known to be flaky. Inside Eclipse, you can achieve the same by passing the
system property ``-DretryFlakyTests=true``.

This profile should only be used by the Scala/IDE integration script to avoid
failing because of flakiness in our regression suite.
Merge pull request #498 from dotta/transient/dont-run-flaky-test-in-test-suite

Added additional Maven profile for skipping known flaky tests