Jshint

- Adds JSHint gem to provide `rake jshint` rake task for checking JavaScript code quality. 
- Performs general cleaning of existing JS code against JSHint. 
- Converts tabs to 2 spaces per best practices.

@monfresh ready for review and merge! This should be rolled over to smcgov/smc-connect also. Let me know how to do that when you get a chance (or point me to email if you sent me those instructions already).