Vote App Improvements

- reorganized common services and directives
- reorganized stylesheets
- added function to get a category
- added category view to vote app
- added candidate and description to landing page
- added dropdown to go to category voting page
Voting

- added voting route
- added vote method for voter resource
- added back to election links for candidates, categories and voters
- loading votes on vote app category view
- fixed categories link on election view