Changed Play Intro / Feature Tour Templates

Signed-off-by: Markus Jura <markus.jura@gmail.com>
Add support for JDK7 watch service

* Automatically uses JDK7 watch service if available and not OSX
  (because on OSX it does polling)
* Otherwise attempts to use JNotify if Windows, OSX or Linux
* Falls back to SBT watch service if all others fail
* Can be configured by end user
* Made the dev-mode tests test all 3 watch services (if available)
* Made the dev-mode tests a little more robust and faster by spinning
  for up to 10 seconds to wait for conditions to be true.
Merge pull request #2950 from markusjura/2.3.x

Changed Play Intro / Feature Tour Templates
Fixed scaladoc for WebSocket.tryAcceptWithActor
Merge pull request #3179 from FabienPennequin/scaladoc-websocket

Fix scaladoc for WebSocket.tryAcceptWithActor
Added documentation about the SBT assembly plugin