Sync with WebODF e50bc588ff3e380178ffabecfe2fbca92bef6aed.

* Keyboard support in iOS and other touchscreens
* Pinch-zoom support on touch devices
* SVG selections that look like those in LibreOffice
* Major speed improvements with all editing operations and cursor movements
* IME support on desktop browsers
* Word-by-word navigation with Ctrl+Left/Right
* Fixes for IE11
* Ability to add/edit/remove Hyperlinks.
Fix header regression
Sync to WebODF dbdc4e91827d460dbf71785a16b7a472bef548a1.

* Fixes a bug with blocky rendering of multi-paragrap selections on iOS.
* Gets rid of the second blue native caret alongside the user's caret.
Fixing disconnection injected twice