* [formats] add better defaults for time + number formatting
* [formatDate] add tests for concise formatDate
* [nvd3] use verbose time format in tooltips
* [number format] improve number format description
* [formats] revert to .3s defaults, tweak number format preview
* [formats] default number vis to .3s
* Use 'count' as the default metric when available
Count is a much better default than the current behavior which is to use
whatever the first metric in the list happens to be.
* Addressing nits
