[CDF-279] - CCC - FocusWindow Constraint does not enforce a minimum window length
* Update protovis, with a feature to allow the Select behavior to respect a certain minimum width and height
* Fixed a bug in which the window length would not be correct when resizing the begin side
* The oper.length property is now being processed when the operation is "new", allowing to set the initial window length
* Ensuring minimum length in other operations is done by controlling oper.value
* Fixed a case where the oper.length0 property wasn't being cast to the correct continuous value type (Date)
[CDF-279] - CCC - FocusWindow Constraint does not enforce a minimum window length
* Unlocked several focus window' s cursor and events extension points, to make it easier to style and extend
* Code formatting
Merge pull request #88 from dcleao/CDF-279

[CDF-279] - Focus Window fixes