Png images on ToolBar

Little change in handling "ImagesFolder" images. If png version of
ToolBar images  are present, they are uses in place of gif version.
Before only gif images were used.
CustomThumbnailHandler property added

Added CustomThumbnailHandler property to allow custom thumbnail
handling.
Removed nuget packages files
Bootstrap 3.2.0 nuget packages files
CKEDITOR nuget package files
Bootstrap 3.2.0.1 less nuget package files
Added packges folder
Bootstrap 3.2.0.1 less nuget packages files
New entries and translations

Added some new english messages with italian translation
Added CKEDITOR Sample