First stab at making dimensions removable.
Forgot to remove the removed dimension.
Avoid exposing position setter.
Better name.
Simplify.
Fix bit twiddling.
Notify filter listeners.
Reset filters prior to removing a dimension.
Added Remove dimension functionality.
Merge branch 'dimension-remove' of git://github.com/jasondavies/crossfilter into dimension-remove

Conflicts:
	crossfilter.js
	src/crossfilter.js
	tesseract.min.js