Boatload of Progress

- Added MBProgressHUD library for activity indicators
- Added photo handler for UICollectionView in TankViewController
- UICollectionView currently pulls from existing library of saved photos
- DUMMY: Instantiated camera when choosing to add new photo.
- Cleaned up appearance of TankViewController
- Cleaned up appearance of SurveyViewController
- Switched to “Add Contact” button for adding items to array when
setting up new tank.
- Switched to “Add Contact” button for adding items to array when
modifying existing tank.

~~Immediate TODO~~
* Save image array to Parse
* Allow user to add new photo
* Download image array from Parse
* Add / remove items from existing array in TankViewController