Sync with webodf fc3a4e615597be18da1e23e03302ef472b9a95e5

* Improve text insertion and paragraph splitting OT -
therefore no more conflict and sync failure when multiple
users insert text or split the paragraph at the same
position.
* Increase performance of virtual selections
Merge pull request #161 from adityab/webodf-sync-06.12.13

Sync with webodf fc3a4e615597be18da1e23e03302ef472b9a95e5