Blender Git Loki

fix for action editor view-selected behaving strangely.
- when an fcurve had no selected keyframes, a default fallback value was used which caused view-selected to include frame 1, even when no selected frames were there.

- the vertical axis was always reset, ideally we would center vertically too but the way this operator currently works we only know about the frame range,
now don't change the vertical scroll when viewing selected since it would always jump to the top of the screen (view-all still acts this way).