Settings rework

In #147 I mentioned settings activity could get some work. This is my attempt to rearrange it.

Layout now looks like this: https://mediacru.sh/76f743ec4082

**Notes:**

 * Two new switches are added: Block Images and Enable Javascripts. The reasoning behind this is somewhat explained in #147, but basically it comes down to enabling easy control of mobile data expenses. Some of users want a quick way to disable everything but the text when they're on mobile data plan.
* Location switch is moved to Privacy and Fullscreen switch is moved to Display activity. They aren't that important to be in main category, IMHO.
* *Restore lost tabs* option could go into General activity, but I left it in Advanced, for now.

Looking forward to opinions.
![prefrew1](https://cloud.githubusercontent.com/assets/913292/5375879/7f502d8c-806f-11e4-8422-1bbc4332b3ad.png)
![prefrew2](https://cloud.githubusercontent.com/assets/913292/5375882/8353e504-806f-11e4-9aab-82ed44f1d43d.png)
![prefrew3](https://cloud.githubusercontent.com/assets/913292/5375884/869fbc42-806f-11e4-81a9-2a7c52d66579.png)
![prefrew4](https://cloud.githubusercontent.com/assets/913292/5375886/89b3428c-806f-11e4-865e-24787fb257b2.png)
![prefrew5](https://cloud.githubusercontent.com/assets/913292/5375887/8dba3048-806f-11e4-9d33-31f8be3e287c.png)
![prefrew6](https://cloud.githubusercontent.com/assets/913292/5375888/9179cdec-806f-11e4-9b5f-8c2fb244e2b2.png)
![prefrew7](https://cloud.githubusercontent.com/assets/913292/5375889/94522bb8-806f-11e4-94cf-14b1b2e596f1.png)