Ignore non-objects in patternProperties.
Ignore non-objects in patternProperties.

Closes #49

python-jsonschema/jsonschema,Julian/jsonschema,eodolphi/jsonschema,sightmachine/jsonschema,jamesmarva/jsonschema,dnephin/jsonschema,mathewmarcus/jsonschema,Julian/jsonschema,wikimedia/operations-debs-python-jsonschema,eodolphi/jsonschema,wikimedia/operations-debs-python-jsonschema,varunarya10/jsonschema