added ng-center-cursor attribute. When false, drag anchor does not center, but remains where div was clicked
Changed ng-center-cursor to ng-center-anchor and moved its assignment into a listener
Removed stray log statement and switched element position on move back to fixed.
Fixed jumping problem when window isn't at top of document
Added button to example.html to toggle ng-center-anchor
Updated Readme to reflect addition of ng-center-anchor tag
Merge pull request #17 from Sanbornh/develop

anchor point on the div will be wherever you clicked it.