Portfolio user role with patient-measure bootstrapping

#### Stories ####
- https://www.pivotaltracker.com/story/show/60860100
- https://www.pivotaltracker.com/story/show/63975020

#### Notes ####
- Added <code>portfolio</code> user role, modeled after existing <code>admin</code> role
- Added corresponding rake tasks, template helper, and measure bootstrapping

## Default user ##
![deafult](https://f.cloud.github.com/assets/456952/1932241/bcdf88c6-7ec9-11e3-91a3-70d25cb3158c.png)

## Portfolio user ##
_Note: Welcome header was used for debugging, has been removed before the commit_
![portfolio](https://f.cloud.github.com/assets/456952/1932245/be789a6a-7ec9-11e3-926c-485513478dfc.png)