Separated TextRange, TextPosition and TextQuote from the TextAnchors plugin
Bugfix about exporting the TextPositionAnchor type
Added extension point for highlight implementations
Fixed a bug spotted by @mitar.
Merge branch 'selector-extension' into peerlibrary

Conflicts:
	src/plugin/textanchors.coffee
Add forgotten textquote.coffee file
Merge branch 'selector-extension' into peerlibrary