[TIDOC-1967] Font and other minor CSS changes to docs

* Changed default body font color to #222
* Bumped default, non-code font size to 14px, including on:
    * Table data cells
    * Tree/navigation menu items
* Brightened &lt;a> link color; assigned new hover color.
* Set font size set to 13px on code blocks, and &lt;code> elements inside &lt;p> tags 
* Removed monospace font family from class header/hierarchy section
* Reduced top padding on API section

See attached image.

![after](https://cloud.githubusercontent.com/assets/408952/4980218/3c2921a4-68fe-11e4-8c3f-ab38e4456cdd.png)