Add SBT cookbook in the documentation
Automatically start things in WithXxx helper classes
Update code to leverage the new way of using WithXxx helper classes
Wrapped the TimeoutException in the unchecked exception

Wrapped the TimeoutException of `Promise#get()` in the unchecked exception for timeout handling.
fix image tag example
Add the form set mapping, fix #2787
Added license files to play/scala seed templates
Bump version to 2.4-SNAPSHOT
Remove play-2.3-highlights template
Merge pull request #2796 from pvlugter/bump-to-2.4

Bump master to 2.4
Issue #2782 Update to Java testing docs
Add notes about closing WSClient cleanly
Merge pull request #2800 from kipsigman/2782-java-test-docs

Issue #2782 Update to Java testing docs
Merge pull request #2772 from Simek/patch-1

fix image tag example
Merge pull request #2792 from filosganga/feature/2787-add-set-form-mapping

Add the form set mapping, fix #2787
Various documentation improvements

* Added YourKit link to highlights
* Added note about Scala 2.11 to highlights
* Added note about local ivy repo to highlights and migration
* Rewrote documntation on extending Play
Add scala cross building to runtests script
Use sbt 0.13.5-RC1 in templates project
Include template tests in runtests script

Signed-off-by: Rich Dougherty <rich@rd.gen.nz>
Add temporary override of js engine dependency