Update measure chords view button w/ text view toggle

### Story ###
- https://www.pivotaltracker.com/story/show/77034560

### Notes ###
- added two buttons to measure settings template for chords and text views
- toggle the appropriate button via <code>.btn-viz-chords</code> and <code>.btn-viz-text</code>
- reset the logic view if measure settings is closed

### Screenshots ###
- chords
  - ![screen shot 2014-08-18 at 9 39 36 am](https://cloud.githubusercontent.com/assets/456952/3951966/40cb514a-26dd-11e4-9b2a-115390251db2.png)
- text
  - ![screen shot 2014-08-18 at 9 39 41 am](https://cloud.githubusercontent.com/assets/456952/3951965/40c3fe90-26dd-11e4-908c-0b1e514a77fd.png)
But you're doing something else using classes; can the button type class be toggled on click too? If you prefer the current implementation that's fine, just offering another option...