Residue rename

[fjarri]

Fixes #351

• Residue -> ConstMontyForm
• DynResidue -> MontyForm
• BoxedResidue -> BoxedMontyForm
• *ResidueParams -> *MontyParams
• residue_params -> params
• params.r -> params.one

Please don't open other PRs before this one is merged, it's a pain to rebase.

[tarcieri]

Your description doesn't quite reflect the names, which are MontyForm instead of just Monty.

For the params names, I'd prefer MontyParams instead of MontyFormParams which seems needlessly long.

Otherwise yes, we should get this rename done ASAP.

[fjarri]

Renamed

[Fethbita]

@tarcieri could you also add the rename const_residue -> const_monty_form into changelog?