CSS changes to the partners section.

* tooltip should have no text transform
* reduce logo size and add top whitespace
* reduce button font size
* remove letter-spacing declaration
* partner title font size
* change partner title color and font-weight
* reduce title padding
* misc padding tweaks
* reduce grey text size on a solution page
Merge pull request #426 from optimizely/ccorda/partners-css-tweaks

CSS changes to the partners section.