CSStweaks3

This pull request implements a number of minor changes:
1. Positions the search icon slightly to the right so it is not cut off like this:
![fixsearchicon](https://cloud.githubusercontent.com/assets/521978/3892936/9d8a1a70-2236-11e4-895a-8ea6d4c93fa0.png)
2. Redesigns form focus state to use blue border and white background rather than yellow. https://github.com/hypothesis/h/issues/1388
3. Fixes spacing between buttons and inputs on the annotation editor:
![toomuchspace](https://cloud.githubusercontent.com/assets/521978/3892961/e19c0322-2236-11e4-95e4-006a7d1cfada.png)
4. Changes 'Private' privacy option to 'Only Me,' repositions the lock icon to be closer to where privacy options are selected, adds icons to the privacy dropdown menu, and adds the .selected class to the currently selected level in the privacy dropdown. This addresses 
https://github.com/hypothesis/h/issues/1377 and looks like so:
![currentinterface](https://cloud.githubusercontent.com/assets/521978/3893026/63b30900-2237-11e4-8db2-bc5db1ca76b9.png)
![iconsfordropdown](https://cloud.githubusercontent.com/assets/521978/3893030/67431e02-2237-11e4-875a-a37ec7792351.png)
5. General CSS cleanup and organization. Creates vender folder for 3rd Party CSS files. 
In our CSS we have styles associated with this. Do we not want them here?