Update Union/Intersection rendering in population logic view

### Story ###
- https://www.pivotaltracker.com/story/show/77034966

### Notes ###
- Set operators are rendered differently than preconditions (lighter font-weight, uppercase)
- Bullets are used when the rationale highlighting is off

### Screenshots ###
- previous default
  - ![screen shot 2014-09-12 at 9 36 14 am](https://cloud.githubusercontent.com/assets/456952/4250286/e514c5d0-3a81-11e4-9185-3eb38efc62b9.png)
- previous rationale
  - ![screen shot 2014-09-12 at 9 36 22 am](https://cloud.githubusercontent.com/assets/456952/4250284/e5121b3c-3a81-11e4-9c33-336543807abb.png)
- new default
  - ![screen shot 2014-09-12 at 9 35 44 am](https://cloud.githubusercontent.com/assets/456952/4250285/e5146e6e-3a81-11e4-8547-956bfa65c4c0.png)
- new rationale
  - ![screen shot 2014-09-12 at 9 35 52 am](https://cloud.githubusercontent.com/assets/456952/4250283/e510857e-3a81-11e4-8d8f-e495e4ebbc5a.png)