Blender Git Loki

More bugfixes for setting visibility of anim channels using VKEY:
* Fixed problem where selecting an individual F-Curve would not set the selection correctly.
Group channels still needed a separate selection check before they get included in the filtered list. I had removed this in an earlier fixing commit today, but overlooked that expanded groups wouldn't get this check. Therefore, group channels would also be flushed on, turning all channels of group on.

* Removed the 'curvesonly' test from deciding whether the selection status + collapsed group fix, from the earlier commit, since this was making a few cases get overlooked (namely for setting visibility toggles, where selected F-Curves in closed and deselected groups still managed to get through)

* Added a debugging print API call for helping with debugging this sort of error in future. It just prints the types of channels being operated on, to easily see what's going on...