Add buttons styles
Adding icons for buttons
Merge remote-tracking branch 'origin/dev-2.1' into buttons

* origin/dev-2.1: (42 commits)
  Add input placeholder style
  add new build files
  add more controls to the settings.html + add charset utf8 for language picker
  add wrapper to glud slider control + fix spinner change event
  fix css style to match the new spec
  cleanup
  Adding disable/ enable funconality, adding styles per spec
  remove textPresetPicker.js
  finishing fontStylePicker
  add FontStylePicker to html
  fix mouse out change event and mouse up change event
  options divider is less visible
  Style changes @barak007
  Better test for input validation
  grunt dev uses this, so adding it back
  cleanup and fix tests
  fix text preset not update whem settings is closed| fix merge error in ui-lib.js
  Styles for input control, adding better validation API
  update grunt file
  add minimal tests for color picker
  ...
Style changes with @Shirly
more buttons css and adding more icons
merge
Changing default font family
Style changes per @Shirly
merge
Add some buttons to samle page
Change buttons to new css classes
Better support for fallback fonts
Support for old button group style
Merge pull request #33 from wix/buttons

Buttons