Start of refactoring.
GWT-693- Added documentation modules to project and plugins for aggregating javadoc.
Fixed doculentation in some plugins.
Fixed PNG uppercase issue in documentation.
GWT-693- Updated modules for aggregating the javadoc per module basis
Merge branch 'GWT-693-Assemble-javadoc-for-modules'

Conflicts:
	documentation/pom.xml
	plugin/deskmanager/deskmanager-documentation/pom.xml
	plugin/deskmanager/deskmanager-documentation/src/docbkx/images/ribbon-search-button-with-configured-searches.png
	plugin/deskmanager/deskmanager-documentation/src/docbkx/images/search-attributes-configuration.png
	plugin/deskmanager/deskmanager-documentation/src/docbkx/images/search-attributes-execution.png
	plugin/deskmanager/deskmanager-documentation/src/docbkx/master.xml
	plugin/deskmanager/pom.xml
	plugin/widget-advancedviews/pom.xml
	plugin/widget-layer/pom.xml