updated UX

-  *add an instrument* should move above the instruments (blue buttons)
- Use the `label-default` class to make the blue labels grey
- the **"-"** needs to be a **"circle -"**: using `glyphicon glyphicon-minus-sign`
Merge pull request #14 from nexus-uw/bug/ux-changes

updated UX
replaced glyphicon with font awesome

- rebuilt dist
Merge pull request #15 from nexus-uw/feature/use-fontawesome

replaced glyphicon with font awesome