Added drag and tooltip to sample#2 HelloGUI
Fix various order of exposition to lua
Added Pool for WorkItem SharedPtrs to save allocation every frame. Its an optional construct to allow the user to create their own pools or not use the pool if they so desire.

Below is the profiling for the Octree and View changes to pooled allocation.

Before:
UpdateDrawables                        35    0.139    0.193    0.135     4.871
SortAndUpdateGeometry          35    0.080    0.135    0.077     2.802

After:
UpdateDrawables                        21    0.082    0.172    0.078     1.735
SortAndUpdateGeometry          21    0.054    0.069    0.052     1.144
Merge remote-tracking branch 'remotes/alexparlett/feature/pooled-work-queue'
Merge remote-tracking branch 'remotes/mike3d/master'
Minor code reorganization of the HelloGUI example. Removed SubscribeToEvents() as it was only used for 1 event and events were also subscribed to elsewhere.