If `node` is in the path, use that instead of the old bundled executables.

Fixes #1600.
Add ability to set target frame rate.
Merge pull request #1679 from AnalyticalGraphicsInc/preferSystemNode

If `node` is in the path, use that instead of the bundled executables
Fix typo.
Fix typo.
Fix typo.
Merge pull request #1676 from AnalyticalGraphicsInc/targetFrameRate

Add ability to set target frame rate.
Merge remote-tracking branch 'origin/master' into performanceMonitorWidget

Conflicts:
	Source/Widgets/Viewer/Viewer.js
Proper view model destruction, and more tests.