Removed "controlsDescendantBindings" from popover binding handler.

I don't know why, but with the latest version of Bootstrap and Knockout, the popover binding can't have the "controlsDescendantBindings" flag set.  With it, I was getting `Uncaught Error: You cannot apply bindings multiple times to the same element.` (related to issue #22?).  Also, it prevents you from having other bindings inside the element with the popover binding on it (issue #25).

This commit apparently fixes both of those issues.

Also, please excuse the whitespace changes, my editor trims all trailing space and ensures a newline at the end of all files.