McHorse's McLib

This minor patch features enormous improvements to keyframe editing GUIs.

• Added value editing through the value field in the dope sheet editor
• Added bezier handles editing in tick and value fields when selecting them (instead of showing tick and value of the keyframe)
• Added multi-selection of keyframes in graph/dope sheet GUI elements:
  • You can select them by Shift + Dragging an area in which all the keyframes will be selected
  • You can select individual keyframes by Shift + clicking on them to select not selected keyframe or deselect selected keyframe
  • You can move multiple-selected keyframes or its handles (depending on selection mode) by editing tick or value fields or dragging
  • You can also duplicate multiple selected keyframes using the same old way of holding alt while clicking else where to duplicate
• Added context menu to graph/dope sheet elements to:
  • Remove selected keyframes
  • Switch selection between keyframe or its handles
• Added new interpolations (with in, out, in/out easings): back, elastic and bounce
• Fixed last keyframe's right bezier handle being editable