Added ARIA support to eui-button

Added aria-role, aria-label, and aria-disabled attributes to
the base eui-button component.
Added ARIA support to eui-checkbox

Added attribute bindings: aria-role, aria-checked, and aria-disabled
Merge pull request #42 from jdjkelly/aria-ify-button

Added ARIA support to eui-button
Fix building and running instructions
Merge pull request #43 from potomak/readme-minor-fix

Fix building and running instructions
Move initializer into separate module
Merge pull request #41 from emberui/mattia/move-initializer

move initializer in separate module
Version bump 0.1.3
replace quote style for regexp
Add release script to automatically bump version, build dist, tag and push
rename main.js to emberui.js