Widget for produce code for embedded datasets

Added  the widget views and a basic interecation  for the dataset embedded.

The file "plugin.py" was changed for add a directory "fanstatic" and
ensure a correct style including the static file in "page.html".
Merge branch 'development' of github.com:zoek1/ckanext-widgets into embeber-widget
Added the size modifiers.

Added the support for modify the size in the inputs and
the predefined sizes. The changes will reflect in the code.

TODO: Support for register the controllers for provide a higher
abstraction, the controller will have the work of generate a different
code. In this case is 'iframe'.
Fixed the button 'Visualizar'
Changed the color from blue to orange in the button "Embeber"
Removed the widget type menu (acordeon)
Changed the boxes labels and added autofill in the size boxes
Merge pull request #7 from zoek1/development

Widget to produce code for embedded datasets