Add Sandcastle.addDefaultToolbarButton

Sandcastle.addDefaultToolbarButton excutes and highlights the toolbar immediately, eliminating the need for breaking out an extra function to call (muddying the code in the process).
Add Sandcastle.reset

When defined by a demo, Sandcastle.reset is called whenever a button or menu selection is main.  This allows for the bookeeping/cleanup code to be cleanly abstracted away from the example-specific code that the user is interested in.
Add missing semicolor.
Merge remote-tracking branch 'origin/master' into sandcastle-defaultToolbar
Update GeoJSON example to use new helper functions

Also changed logic to defer execution of the default action until loading is finsihed; this way we can run the reset function before the default action.
Merge remote-tracking branch 'origin/master' into sandcastle-defaultToolbar

Conflicts:
	Apps/Sandcastle/gallery/3D Models.html
Merge remote-tracking branch 'origin/master' into sandcastle-defaultToolbar

Conflicts:
	Apps/Sandcastle/gallery/Billboards.html
	Apps/Sandcastle/gallery/Terrain.html
Merge remote-tracking branch 'origin/master' into sandcastle-defaultToolbar
Better `onselect` behavior in Sandcastle.
Merge pull request #1956 from AnalyticalGraphicsInc/sandcastle-defaultToolbar

Sandcastle tweaks