Gridstack doesn't reinitialize when options changed

[d0coat01]

I really appreciate the port to angular. One thing I noticed when switching up the options is that the gridstack directive doesn't detect the changes.

Perhaps add a watch on the options variable in the directive?

[epelc]

I partially did this with #21. It is for the widget options but same idea.

Maybe use as a base/reference for anyone looking to add support for this.