Full integration of Column Selector component into settings

- Settings controller updated to watch the spreadsheet.url value, upon new value it resets the column selector and retrieves the new column data and updates the column selector accordingly
- Columns setting service updated to add the id of the column to each column object of the column names array being returned
- Removing unused localization values in translation.json
- Settings HTML importing columns settings service and removing unnecessary ng-model directive on column-selector
Merge pull request #21 from stulees/master

Full integration of Column Selector component into settings