ENYO-2288: add moonstone button on palette
ENYO-2288: add moonstone button on palette

Modified moonstone.design file.

Change:
- http://nebula.palm.com/enyojs/lib/moonstone/samples/ButtonSample.js shows several types of buttons.
  but, they are not directly related with moon.Button kind. Most of them relates to CaptionDecorator, Group

Benefit:
- Add moon.Button kind component on default type only.
- We can add more types when other types or kinds buttons are defined or requested to add palette in the future.

Test Result:
It will be uploaded seperately on gitHub log message.

Enyo-DCO-1.1-Signed-off-by: Sunggye <shiftpwr@gmail.com>

mcanthony/moonstone,mcanthony/moonstone,enyojs/moonstone,mcanthony/moonstone