added example. Improved handling of options for hierarchical view.

See https://github.com/almende/vis/issues/1568#issuecomment-171961393

-Keep single defaults location
-Update documentation on formatting function.

- Accepted pull request #1544, thanks @felixhayashi!
- Fixed documented bug in #1544.

not sure but for some reason, once the colorpicker is open, the buttons won't work correctly and the huecircle jumps back.

- Fixed #1528, #1278, avoided ID's being cast to string for methods that return ID's as well as storePositions casting to string.

Some fixes and cleanups after the large rewrite.

Provide the DataView.map() method similar to the DataSet one.

Fixes DOM API deprecation warning in Chrome.
Please see: https://www.chromestatus.com/features/5724912467574784

This is an improved version of PR #1501.

Minor cleanup

-Draw points in bar icon if appropriate
-Introduce point icon
-Cleanups

Add some enhancements for stacking (especially with regard to shading)

-Never push into arrays that have a known length
-Move more functions back into the main updateGraph method

Fix no-group data input case.

Separate shading from line drawing (fixes drawing order)
Cleanup of draw code
Fix icon-shading CSS override