Added support for undoable animation.

with cmdx.DagModifier() as mod:
  node = mod.create_node("transform", name="animatedNode")

# Set some keys
with cmdx.DagModifier() as mod:
  mod.set_attr(node["tx"], {1: 0.0, 5: 2.0, 10: 0.0 })

# Set some more keys
with cmdx.DagModifier() as mod:
  mod.set_attr(node["tx"], {20: 0.0, 25: 2.0, 30: 0.0 })

cmds.undo()  # Keys 2 bye-bye
cmds.undo()  # Keys 1 bye-bye
cmds.undo()  # Node bye-bye

Notice that it boths creates the (correct!) animation curve node (linear for translation, angular for rotation, for example), depending on the plug type, or edits it if one already exists.

And more:

• Support for tangents and AnimCurve
• AnimCurve.key(interpolation) was renamed tangents
• Support for plug.connection(plugs=("name1", "name2") to match by name
• Add Tm.setRotatePivot and setRotatePivotTranslate
• Add Tm.setScalePivot and setScaleivotTranslate
• Add cmdx.time() and cmdx.frame() conversion functions, like math.degrees() and math.radians()
• Support matching array-plugs by name
• Repair cmdx.lookAt()