Hopefully all the changes we need.

Conflicts:
	source/scenario/scenario.js
- Fixed a bug where the context wasn't being passed in
- Removed a test warning - it passed the test
- Cosmetic fix.
Added support for debugging output so that you can see what's going
on in the triggers.  The actual output is commented out, so that
the log isn't spammed.
Removed dead code.
Bug fixes and refactors...
- Fixed the opaque grid tiles
- Made the background music (but not success/failure) into a
  sound group so that they'll just replace each other
- Stop all the appropriate sounds on success/failed
- Global trigger to enable/disable helicam based on whether
  its in your inventory
- Don't hide blockly on success
- Cleaned up the spot where we clear scenario triggers
- Add helicam to inventory for scenario 2 and 3
- Added a comment
- Get the pan added back in.
Remove the pan from where it doesnt' belong.
Rethought the best places to load/clear the triggers.  We now only do that on success.
A couple tweaks based on Brett's comments.
Merge pull request #257 from virtual-world-framework/trigger-system-improgements-take-2

Trigger system improvements