And another one.

Add tangent output to torus knot node and optimize its code

- add tangent calculation and output to the node
No need to restrict the node's phase parameters to only positive values.. the spin/revolution phase can go in both directions.
- minor optimization
- conditionally calculate normals and tangents based on node extra parameters (on by default)
- remove the min bounds from the phase parameters
- update comments and documenation
- cleanup unused code
- PEPify the code