1. Camera now has a virtual look-at point. Camera can now rotate around the look-at point or as well as itself. No focus will be lost during camera operation (issue #2039). New object can place at this look-at point(view center).
2. Better camera close-look - adjust pos/zoom of camera and make view frustum fit the calculated bounding box of selected nodes and components.
3. Double click component in Hierarchy Window can also look close to the node.
4. Camera smooth interpolation - pos/rot/zoom smooth interpolating for close-look, top/front/side view switching.
5. Removed MouseWheelCameraPosition to make camera less confusing.
6. Key/Mouse changed - Added F key(Standard Hotkey, many popular tools use this key) and NumPad Period(Blender Hotkey) for camera close-look. Moving middle mouse button for orbiting around look-at and right button movement for orbiting around camera itself (For standard Hotkey).
