Add viewer/editor/adder elements to the document.body, regardless of whether annotator is created on a sub-element.

This is to fix clipping issues when annotating an element inside an ExtJS gui, which clips anything outside.

I don't think this will break things, but I'm not sure.
Add some tests for turning dom ranges into character offsets and back again
fix brokenness in range_spec. It was overwriting document.createRange with a mock and breaking my tests
Allow the annotator elements to be added to the document body, instead of @element
fix image tests
More code for binding annotator gui elements to document body
fix the store plugin for image annotations
add charrange tests to the runner
Fix up the charrange selection code
Add code for removing annotator from an element