Python API - Re-Design Collection Compiling

[david-cattermole]

Using the mmSolver.api functions we can compile a Collection into keyword arguments for the maya.cmds.mmSolver plugin command. The code to do this is currently ~1000 lines, and the logic is spread into both the mmSolver.tools.solver sub-package and mmSolver._api.collection module.

Now we have a better idea of how the solver should work, we should redesign and refactor this component. Ideally we should maintain backwards compatibility, but this is not critical.

Goals / Features:

• Avoid needing to create multiple kwargs for each frame.
• Try to use Python generators to "yield" kwargs, rather than pre-compile them.
• Create a way to detect individual "chunks" of nodes; each chunk can be solved separately.
• Validation should not require compiling every-single-kwarg. For example, we don't exactly care about the data, but instead the "connections".
• Logic for early-exit of the solver process.
• Logic for re-initializing the mmSolver command if a new minimum may be found (must have a limit of "re-attempts", must not loop forever).
• Provide a system of user feedback for solver information (not just SolveResult classes); for example tell the user how many "errors vs parameters" are currently set up.

Related to issue #18 and #57.

[david-cattermole]

Commit 04a1e49 now completes this issue. The commit is now merged into the master branch. Any extra features will be covered by a newly created issue.

The new code supports faster validation as a part of the API, without needing to compute the Collection a second time.