Make setting input widths easier with bootstrap 3

* Bootstrap automatically expands all form inputs to 100%, meaning shorter inputs need grid wrappers to constrain them. This produces extra markup, especially when a grid isn’t already being used.
* Create some input helpers that restrict the width of inputs based on standard column widths.

![screen shot 2014-07-03 at 14 37 21](https://cloud.githubusercontent.com/assets/319055/3470133/47b1b1d8-02b7-11e4-8425-79424fbfca39.png)