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 #3173 from jroper/jdk7-watch-service

Add support for JDK7 watch service
Changed Play Intro / Feature Tour Templates

Signed-off-by: Markus Jura <markus.jura@gmail.com>
Build improvements - less repetition
Added documentation about the SBT assembly plugin
Fixed scaladoc for WebSocket.tryAcceptWithActor
Removed usage of festassert from play-java-intro template
Merge pull request #3172 from jaceklaskowski/sbt-build-improvements

Build improvements - less repetition
Change order of path to activator in PATH variable

I had problems with setting the path to activator and/or play when the path came after the content of the PATH variable when using ubuntu. I think it is less error-prone when we add the activator path at the beginning of the PATH variable.
Merge pull request #3181 from jroper/sbt-assembly-docs

Added documentation about the SBT assembly plugin
Ensured WatchService watches directory recursively

* Also fixed MatchError on FreeBSD
Merge pull request #3187 from jroper/watch-service-recursive

Ensured WatchService watches directory recursively
Upgrade to sbt-native-packager 0.7.2.
Merge pull request #2922 from nastra/master

Change order of path to activator in PATH variable
Forward port docs from 2.2.x branch regarding new preferred way to use with intellij
Merge pull request #3192 from benmccann/intellijdocs

Forward port docs from 2.2.x branch regarding new preferred way to use intellij
Merge pull request #3191 from benmccann/native-packager-0.7.2

Upgrade to SBT native packager 0.7.2