Also:
* Made a fragment with a null range become a null fragment
* Fixed incorrect order of arguments for binding a handler to transact event
* Added getters for surface, document and range
* Fixed several instances of passing a document instead of a surface into the constructor of a new surface fragment
* Fixed closest mode in expandRange - needed to check if parent existed before checking for it's type
* Fixed uses of ve.Transaction (doesn't exist) that were supposed to be uses of ve.dm.Transaction (does exist)
Change-Id: Ide13d9d2d1637399188c98c2e8b6e0826caeecc4
