Add 'stirling.test' package

Move the NASDAQ OMX SoupTCP 1.0 test framework core into the
'stirling.test' package.

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
Move 'stirling.test' package to 'main'

Make it possible to to use 'stirling.test' in projects that depend on
the 'stirling-core' project.

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
Extract TestSilvertipActor from TestActor

Make it possible to use the test framework both with Silvertip and
non-Silvertip test actors.

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
Merge pull request #140 from jvirtanen/features/test

Add 'stirling.test' package