Add module for simple starting radare2 from framework

Start reverse framework radare2 from viper.

Without web-server frontend:
viper > r2

![2014-09-25 01 04 24](https://cloud.githubusercontent.com/assets/1186777/4396217/efa0ceda-4432-11e4-97f1-d50810fbe8b7.png)

With web-server:

![radare2-webserver](https://cloud.githubusercontent.com/assets/1186777/4396229/031e6b48-4433-11e4-9031-215fd3aa7c4b.png)