Refactor internals to not use params

[michaels10]

Due to the history of MM3, the dictionary params is used as a means of passing around parameters. This is confusing, prone to breakage, and unidiomatic. We should put some time into removing any mention of it in the internal code.

This is a non-trivial undertaking, but it shouldn't be too tricky.

The main pain-point is load_stack, which relies heavily on params and is very common in the code.

The broad-strokes steps are:

• Make a new version of load_stack that does not rely on params.
• Make each file use this new version of load_stack
• Deleteload_stack entirely.
• Go through each file to remove params dependency

[michaels10]

The big thing holding this back was 'load_stack'. This function was removed -- thus, now it is on any contributors to remove as much of 'params' as possible wherever they can.