Handle schemas with multiple complex schemas

[charjr]

Related to #179 and will likely be fixed with the same change.

Currently it is assumed that if any xOf is present, you wont also have yOf or zOf.

This may not always be the case, currently we would not handle a schema like this:

schema:
  allOf:
    ...
  anyOf:
    ...
  oneOf:
    ...

Membrane would see the allOf and ignore anything else:

schema:
  allOf:
    ...