Added option in Region settings to show experimental servers

@Wizecoder and I added the experimental server option in the Info>Settings>Region view. It shows the alerts as described in issue #243 (plus succinct titles for the alert box), and will choose the automatic region if it exists if turning off from an experimental region. If it does not exist (i.e. the user is 100 miles outside any known region), it will automatically choose the first one in the list (in this case, Atlanta), or let the user select. If for some reason no regions load, it sets it as nil (i.e. the "Out of OneBusAway Service Area" message will be displayed until the user can manually select a region again).  Here are some screenshots of what it looks like:
![switchscreenshot](https://f.cloud.github.com/assets/4627278/1969532/eb91b594-82f3-11e3-87e0-2b906b862949.png)

![alert1screen](https://f.cloud.github.com/assets/4627278/1969533/eec06c10-82f3-11e3-8e13-378e7bdc6477.png)

![alert2screen](https://f.cloud.github.com/assets/4627278/1969535/f398cdd6-82f3-11e3-8399-38d683b4bf33.png)

@barbeau Let me know if everything seems fit, and I'll pull in.