Indicate change with flashing background on measure population tab switch

#### Story ####
- https://www.pivotaltracker.com/story/show/62069906

#### Notes ####
- Added <code>indicator-on</code> and <code>indicator-off</code> classes for rendering flashing background on measure view page elements that change between measure populations on population tab switches

#### Screenshot ####
![screen shot 2014-03-20 at 10 42 40 am](https://f.cloud.github.com/assets/456952/2473136/8317b2de-b03e-11e3-9cb4-b9c9ca162aa0.png)