New Login Theme

Gutted the login using the latest bootstrap css pulled from the bootstrap repo to utilize a few classes I wasn't seeing that I was using while tinkering on bootply. Fixed the CP issue regarding padding on the sidebar the update caused. Made the login.css easy to apply simple themes and stuck a couple little examples in there. Removed the pretty checkables resources now that it's not being used. Added a couple ZPanel logo images (white and black) for light and dark themes. Also added a function to reset the URL when you close an alert, was buggin me while I was refreshing and testing dunno if this needs to stay not sure how older browsers will react to it.

![selection_004](https://f.cloud.github.com/assets/1835077/829592/818b8a1c-f0ea-11e2-8086-826454b6c1a4.png)
![selection_005](https://f.cloud.github.com/assets/1835077/829593/833a6fa4-f0ea-11e2-9b9b-7305edd430a6.png)
![selection_006](https://f.cloud.github.com/assets/1835077/829594/856ff7a8-f0ea-11e2-8603-b56f56b11bef.png)