Normalization fixes

[nkern]

Some major changes to the internals.

• Supports multi-path normalization / transformation
• Supports
• Supports flow matching
• Fixes conditional CFG bugs: supports discrete and continuous class labels
• Implements EMA and post-hoc EMA
• Implements Min-SNR weighting
• Removed setup.py in favor of pyproject.toml entirely

Remaining:

• when installing locally for a 2nd time via pip install . on HPC server I'm getting some build errors (doesn't happen on my laptop); however, it works with an editable build pip install -e .. This should be resolved in the future.