add MGF1 class, docs, tests
change MAX_LENGTH to be an object rather than a byte string
make attributes of MGF1 private since that's our general convention
document MAX_LENGTH
Add loader and loader test for FIPS DSA KeyPair vectors
Decrease loader test size
Use iteritems from the six module for Python 3 compatibility
Remove some of the vectors in the loader test
Change flag to a bool
Add the vectors for different (L,N) pairs again for the loader test
make MAX_LENGTH an object()
update jenkins URL to use TLS
Added backend check to twofactor primitives
Removed pretend stub
Merge pull request #798 from Ayrx/add-backend-check-to-twofactor

Added backend check to twofactor primitives
Merge pull request #789 from skeuomorf/loader

Loader for DSA FIPS KeyPair vectors
Added backend check to kdf primitives
Fixed pep8 error
Removed newline from start of methods
Merge pull request #796 from reaperhulk/update-jenkins-url

update jenkins URL to use TLS