Remove range.normalize (not needed), use range.isCollapsed more often

The normalize method doesn't need to be explicitly called anymore because there's not any code that changes the properties of a range directly anymore.

A good way to prove it's not needed anymore is to move the normalization logic to the constructor and then add "console.log(this.from <= this.to );" to the normalize method - you will find that it's never actually doing anything at all because the range was normalized by the constructor.

ve.Range
* Moved normalization logic to constructor
* Removed calls to normalize method
* Removed normalize method
* Simplified documentation for flip method
* Whitespace fixes

ve.Document, ve.dm.Transaction, ve.dm.Surface, ve.dm.Document, ve.ce.Surface
* Removed calls to range.normalize
* Switched to using range.isCollapsed instead of comparing properties directly

Change-Id: I80bfd06f88579c34dce2083c2b70d63ab92f1275