Fixes for cursor "selection creep" when applying styling to a complete paragraph

Reproduction steps:
1) Open http://ci.kogmbh.com/deploy/WebODF/webodf-ci-b23-g163c84d5/editor/localeditor.html
2) Click to the left of the second heading ("It can embed fonts too!")
3) Click and drag the selection to the right of the heading (to select the complete heading)
4) Now click the bold button a few times and notice the selection expanding