Split GridTransformer functionality

[Barsonax]

Summary

The functionality of the GridTransformer class should be splitted into 2 classes: -A Transformer class that simply transforms a position to local or world space -A GridTransformer class that inherits from Transformer and adds grid related transformations to this.

Lastly add unit tests that check if these classes behave properly.

Analysis

• Non grid networks can use the Transformer class and grid networks can use the GridTransformer.
• Preparation to add proper transformer support that will make it possible to move the network after it has been created. Possibly also rotations in the future (might be needed for iso grids?). Currently the positions in the nodes are not local but worldpositions.

[Barsonax]

To properly refactor the transformer classes I decided that from now on nodepositions will be relative to the network they are in.

[Barsonax]

Implemented in develop