Hook up Cesium and Leap Motion Controller.
Merge branch 'master' into leap

Conflicts:
	src/app.js
Merge branch 'master' into leap
Prevent globe from disappearing.
Add zoom.
Enable gestures. Add pick gesture.
Merge branch 'master' into leap
Do nothing if a hand is not detected.
Enable gestures the right way.
Merge branch 'master' into leap

Conflicts:
	src/app.js
Merge branch 'master' into leap

Conflicts:
	src/app.js
Merge branch 'master' into leap
Updated screenshots
Added team photo
Show metadata for mouse over item, otherwise selected item
Updated README.md
Use Cesium's update loop instead of the Leap's.
Add Page to missions.json
Add URL to NASA page
Add query parameter.