Make `==` , `hash` not depend on canonicalize?

[oxinabox]

#230
made == and hash use canonicalize.
JuliaDiff/FiniteDifferences.jl#111 does the same to FiniteDifferences.to_vec
this is a problem if ever we are having fields that for example match to the properties rather than the fields.
This was brought up in JuliaDiff/ChainRules.jl#285 (comment)

One option might be to introduce a Maybe we should have a canonicalize(x, mode=propertynames) or just always use propertynames rather than fieldnames

But specifically for these cases:
For isequals instead we should probably check that any fields not in both are iszero.
For hash we might be able to drop any fields that are iszero or maybe just any that are Zero.

to_vec is harder and not for this repo.