Cleanup

- Get rid of g_objectRbt
- Get rid of g_objectBeingManipulated
- Refactor usage of g_currentViewIndex
- Add new global var g_currentView, which is now used instead of g_currentViewIndex in many places
- Get rid of 'o' key functionality. Picking makes that unnecessary
Merge branch 'master' of github.com:michaeltingley/CS175