- Introduce WorkbenchLayout SPI 
- Added two custom PanelTypes for HAL: SplitLayout and LayoutPanel
- Allow for PanelDefinition parent traversal
- Added PanelPresenter.selectPanel() API
Merge branch '0.5.x' into UF-97

Conflicts:
	uberfire-api/src/main/java/org/uberfire/workbench/model/PanelType.java
	uberfire-api/src/main/java/org/uberfire/workbench/model/Position.java
	uberfire-workbench/uberfire-workbench-client/src/main/java/org/uberfire/client/WorkbenchEntryPoint.java
	uberfire-workbench/uberfire-workbench-client/src/main/java/org/uberfire/client/workbench/AbstractPanelManagerImpl.java
	uberfire-workbench/uberfire-workbench-client/src/main/java/org/uberfire/client/workbench/Workbench.java
	uberfire-workbench/uberfire-workbench-panel-managers/uberfire-panel-manager-nswe/src/main/java/org/uberfire/client/workbench/pmgr/nswe/NSWEPanelManager.java
Leverage WorkbenchLayout instead of PanelManager to setup the outer most workbench structure
WIP
Mostly fixed startup for uberfire-tutorial.

Still need to check the showcase apps and address UF-112 for panel content sizing issues.
javadocs, tests and code cleanup
docs and comments , author & date tags
Remove SelectablePanels interface. It was not used.
remove system.out calls. additional javadocs added
Document part manager
UF-112: fix onResize() behaviour to work as intended by GWT's LayoutPanel system

The general concept that onResize() should only bubble down from the root to the leaves
and that parents are responsible for ensuring that their direct children are laid out within their
bounds (usually by filling the parent completely) has proven correct.
Temporary fix for DnD boundary panel (won't be needed after merge with hal/UF-97)
Improved JavaDoc
Added explicit symmetry to the way panels are created and destroyed (both are done by PanelManager via BeanFactory now). Refs UF-99.

The TemplatedPanelManager and the JSWorkbenchPerspectiveActivity need to be modified similarly to the NSWEPanelManager
and the AbstractWorkbenchPerspectiveActivity before this work can be merged.

Also, some new unit tests are required before this is merged upstream.
Pre-merge cleanup for previous commits
New unit test for PerspectiveActivity impls. Will be extended to other Activity types.
Added new explicit removePartForPlace operation to the PlaceManager unit test
Added unit test for PanelManager impls; starts by just testing behaviour of AbstractPanelManager itself

In the future, this should be merged with BasePanelManagerTest, and there should be a subclass
which tests NSWEPanelManager and another for TemplatePanelManager.
Added tests for PanelManager add/remove of parts and panels
Cleaning up leftover printlns