fix: get_properties no longer sorts keys in alphabetical order

[jgroth]

The get_properties method sorts the properties in alphabetical order. If the schema defines a Meta schema like the one below, the properties will most likely be in the wrong order

class Meta:
    ordered = True

[coveralls]

Coverage remained the same at 99.149% when pulling e80cdd7 on Lundalogik:respect-ordered-dict into c032d1a on fuhrysteve:master.