Introduce SOURCE_PATH generator variable.

This means that the source path is no longer hardcoded as ${ROOT}/source.
Merge branch '6714-generator-refactor'
Merge branch '6714-generator-refactor'
Merge branch 'master' of https://github.com/qooxdoo/qooxdoo
Merge remote-tracking branch 'upstream/master'

Conflicts:
	tool/bin/generator.py
Merge branch '6714-generator-refactor'
Merge branch 'master' of https://github.com/qooxdoo/qooxdoo

Conflicts:
	tool/bin/generator.py
Get the right event target of IE as well.
Always return a animation handle.
Merge branch '6714-generator-refactor'
Merge remote-tracking branch 'origin/master' into 6779-dry-base-json
Merge branch '6779-dry-base-json'
Merge branch '6714-generator-refactor'
* Fixed Bug: IE10 did not finish animation. Back navigation did not work.
* Fixed Bug: Fade transition did not work.
* Fixed Bug: RadioButton did react slow.
* Fixed several carousel showcase bugs on Nexus S (Android 2.3)
[BUG #6997] Dialog page: Busy Indicator should Disappear after some While
Typo fix.
Fixed the detection if CSS or JS animations should be used. This applies to all non webkit browsers.