Change it to be compatible with Twitter Bootstrap

[xavadu]

I change the code to instead of specify device, specify a Twitter Bootstrap Media Query
http://getbootstrap.com/css/#grid

It is better approach by diferent points:

• Isn't necessary match about isSmartDevice().. (a list that need maintenance and not cover all the devices),
• Also work for a window resize (not necessarily a device)

TODO:

• The watch to recreate the element if the size change isn't working
  The config $watch isn't working #6