Updated to fontawesome 4.1 and rotation animation added for BootstrapButtons

* Updated to Font Awesome 4.1
* Changed padding calculation for `BootstrapButton` so rotation animation can be used
* Added rotation animation to control `BootstrapButton` icons seperately
* Changed `bbutton_size` attribute type to `enum` so IDE will give an error if wrong type is given
* Fixed for some example problems like size was set as `"warning"`
* A new layout added to show rotating BootstrapButton icons