WIP: Fix 48

[marcvs]

Addresses #48 :

Handle matching in case value is not a list.

Yet, the test fails, even though only one email of two email addresses needs to match

[marcvs]

@lburgey: Before I remove all references to OneOf, I thought you'd better have a say on this ;)

[lburgey]

@lburgey: Before I remove all references to OneOf, I thought you'd better have a say on this ;)

I think you can remove it, so go ahead

[dianagudu]

I'd suggest to keep OneOf and simply subclass from N_Of with n=1. Not just because I use it in motley_cue :), but I'd imagine it's a common use case, and then it's just nice to have a shorthand.

[marcvs]

ok