Added shared tests back

Now we can configure tests so they can be shared across multiple servlet
container backends.  This works against both SBT 0.12 and 0.13
Hack to get a Tomcat restart functionality to pass the test

For some reason Tomcat usually returns a 503 on the first request after
a restart.  So we make a extra request before we actually check that
expected page is up.
Fix for restart functionality

Order of task dependencies does not guarantee ordering of execution.  So
sometimes start would be called before stop.