- add 3 nodes: Quaternion In, Quaternion Out and Quaternion Math

Quaternion In:
Provides conversion from various quaternion components to quaternions (selectable via the mode option):
- components wxyz
- angle + axis
- euler angles
- matrix

Quaternion Out:
Provides conversion from quaterions to various quaternion components (selectable via the mode option):
- components wxyz
- angle + axis
- euler angles
- matrix

Quaternion Math:
Provides various quaternion arithmetic operations:

ADD
SUB
MULTIPLY
DIVIDE
ROTATE
DOT
DISTANCE
NEGATE
CONJUGATE
INVERT
NORMALIZE
SCALE
MAGNITUDE

Note: some operations take multiple quaternion inputs (input list grows as new sockets are connected), two quaternion inputs, single quaternion inputs, or quaternion + scalar input.