Add a ServerSSLEngineProvider, to allow for configuration hooks into the SSLEngine.

This is needed for where the engine needs configuration (notably for client authentication) before being passed on to the SSLHandler.
Better class handling, using isAssignableFrom.
Merge pull request #2696 from wsargent/fix-ssl-client-auth

Add configuration hooks into NettyServer createSSLEngine
Added note about session.maxAge changing to migration guide

Also added a MigrationHelper plugin that detects errors caused by not
following the migration guide.
Make RunQueueSpec more stable on slow machines. Fixes #2769

Reduce the minimum amount of concurrency used by at least 10. The actual
level of load should dynamically scale up, so it is OK to start at a
lower baseline.

This change will hopefully make our CI tests more stable.
Merge pull request #2751 from jroper/2751-session-maxAge-migration

session.maxAge used to be in seconds - now its in millis
Merge pull request #2777 from richdougherty/runqueuespec2

Make RunQueueSpec more stable on slow machines. Fixes #2769
Fixed deploy API docs script
Fixing java8 build
Fixed running scripted plugin in Scala 2.11 build

The fact that we weren't publishing artifacts when building against
Scala 2.11 was causing the scripted tests to break.  It probably would
have broken other things too.
Fixed Java 8 build

Don't assume that there is only 1 method on a class when Java 8 adds
many synthetic methods to it when you have lambdas.