Backport downstream fixes

Hi @seanahrens, this ports some of the downstream fixes back into the master branch for OPN.

**Documentation**
- Added general installation instructions, along with some prerequisites

**GUI Styling**
- Replaced all instances of glyphicons with font-awesome icons
- Updated some social profile error displays when updating the social profile

**Better Handling HTTPS**
- Removed protocol specific JavaScript and image asset links that would cause browsers to complain about serving secure and non-secure content

**Bug Fixes**
- Fixed a bug that prevented the next survey from being displayed.