Rework / overhaul DeformNet code.

[Algomorph]

DeformNet code is mostly encompassed in one god-function. This makes it very difficult to parse, understand, debug, and tune. It needs to be split up into smaller functions, without loss of functionality.

• Write test that envokes the DeformNet forward function with consistent output and high branch coverage, to verify there was little to no loss of functionality after the rewrite.
• Rework the program arguments / parameters to be more managable at runtime (i.e. inroduce ext_argparse).
• Make sure the test(s) of the alignment have full coverage of the DeformNet forward function using various setting conditions.
• Split up the function into logical units.

[Algomorph]

Last step is being worked on in the greg_devel branch, e.g. 290c1d1 +/- 3-5 commits