disable create_reference_number

this fixes the following errors when using the rate():

ERROR:suds.resolver:(ns2:ReferenceNumberType) not-found
ERROR:suds.resolver:path: "ns2:ReferenceNumberType", not-found

This should be fixed at a later point.
Merge pull request #17 from r3dfish/master

disable create_reference_number
Update ups.py

Typo in ups.py label function
Merge pull request #18 from r3dfish/master

Update ups.py
Merge pull request #3 from benweatherman/master

Pulling new updates for minor fixes.