Conditionally style dates in a potential range selection.

[mkartchner994]

For date range, I think adding something like this would be helpful https://github.com/deseretdigital/dayzed/blob/master/src/dayzed.js#L89

It would give us the ability to add styling to dates in between a potential range selection like how react-dates does http://airbnb.io/react-dates

[mkartchner994]

After adding the range example to the repo - #9 - I realized that adding logic to the src for dayzed wouldn't really make styling ranges that much easier compared to just handling it in the created <RangeDatepicker> like in the example.

Because of this, I think we can just point people to the Range example, and let the user handle the logic for it in their specific use case.