JERSEY-2501: Jersey 2.8 breaks JerseyTest unit tests under TestNG
JERSEY-2502: JdkHttpServerFactory does not return HttpsServer when https:// URI is used.

 - ability to run TestNG tests in parallel (see JerseyTestNg and TestNgState)
 - find first available port for container if 0 is passed as the port
 - added some parallel TestNG tests
 - updated documentation

Change-Id: I6be235f40b01a055d64ed1ac6279e98f431d085d
Signed-off-by: Michal Gajdos <michal.gajdos@oracle.com>
Merge "JERSEY-2501: Jersey 2.8 breaks JerseyTest unit tests under TestNG JERSEY-2502: JdkHttpServerFactory does not return HttpsServer when https:// URI is used."