support for lists, images and Webkit 

This has support for images, lists, H-elements, etc. and makes ICE compatible with Webkit (with the exception of Copy-and-paste handeling). It also makes cleaner deletion in selection mode (it deletes each node individually rather than wrapping everything within the same block in one single delete node).

Tests are provided for image and list deletion.

See also https://github.com/NYTimes/ice/issues/48 https://github.com/NYTimes/ice/issues/42