Transformations Refactor

[pshriwise]

Description

We have a few places where transformations are applied. These are currently serialized into XML and read into vectors on the C++ side. It would be nice at some point to create a class on the Python side for transformations that can be exported to an XML element (<transformation>) and a corresponding struct in C++ that holds the transformation values.

Alternatives

Leave it as-is. This isn't a huge priority, just an opportunity for improvement :)

Compatibility

This may cause compatibility issues, particularly on the Python side where these transformations are defined.

[gonuke]

@connoramoreno - we sort of discussed this today...

[pshriwise]

Noting here that it would probably be good to include a rotate_first option on these transformations to indicate the order of rotation/translation.