Fixes issue #549.
`jQuery.fn.parentsOrSelf` fixed.
`editor.mainContainer`: fixed critical bug in it and some calls to it.
`editor.switchTo`: node.nodeValue -> node.value
`jQuery.fn.parentsOrSelf`: Fixed.
Remove two blank trailing lines from `core.js`.
Merge pull request #549 from wymeditor/issue_549

Fixes #549 Chrome: root DIV not converted to P with enter after LI ending in inline tag