remove some custom css

mainly in navbars, where we were doing custom things that bootstrap already did with classes.

Came up when I was working on some things in the text editor, where various default elements didn't render properly due to some custom things we were doing elsewhere.

This did require the removal of some LESS inheritance for navbar buttons, because it doesn't work properly. This seems like a bug in LESS, or maybe a shortcoming of how the bootstrap LESS is defined. In any case, the result of setting a collection of btn classes in LESS is very different from assigning the classes individually, so this uses regular css classes where needed.

Before:

![screen shot 2014-12-04 at 23 11 44](https://cloud.githubusercontent.com/assets/151929/5312266/34ef2378-7c0b-11e4-9725-0277c516ba7a.PNG)

After:

![screen shot 2014-12-04 at 23 11 44](https://cloud.githubusercontent.com/assets/151929/5312267/3a562e7e-7c0b-11e4-8285-19b341180b8c.PNG)

ping @ellisonbg, since this is technically a style PR, though it doesn't actually change any style significantly, only how it's accomplished.