Add support for draft-04 multipleOf.
Add support for the draft-04 not keyword and unit test.
Add support for draft-04 allOf, anyOf, and oneOf keywords.
Optimize anyOf. Stop after first matched schema.
Correct 'property' array key value in validation errors.
Merge pull request #49 from mchiocca/master

Support for Draft v4 multipleOf, not, allOf, anyOf, and oneOf keywords.