fix(rxApp): up font weight from 200 -> 300; fix #344

Mac OSX: 
Before:
![image](https://cloud.githubusercontent.com/assets/706039/3320329/71a364b2-f729-11e3-9a92-631352dde2ca.png)

After:
![image](https://cloud.githubusercontent.com/assets/706039/3320246/876f2f66-f728-11e3-940e-76dde44daaa1.png)

Linux (fuzzy b/c using sauce labs): 
Before:
![image](https://cloud.githubusercontent.com/assets/706039/3320258/ad08336c-f728-11e3-8a69-c3dd10316bd7.png)

After:
![image](https://cloud.githubusercontent.com/assets/706039/3320274/cd850bd8-f728-11e3-9159-04d0eaaf9edd.png)