Superficial changes to UI, first pass

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* 'Download as: JSON' removed colon
* More breathing room for date picker, increased letter-spacing
* Added gradient to Update button
* Made dashboard titles more consistent
* Cleaned up list on langing page
* Tooltips' background element is now colored rather than the border
* Removed colon from "Apps:" in tooltip
* Vertically aligned Regions drop down box with rest of components in pane
* Added a set of circles 4x larger than existing ones at same positions and attached mouseover/mouseout listeners to them. This makes it easier to mouseover an individual data point
* Increased tooltips' left offset 
* Removed mouseover transition
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