Fixed attribute converters

Lower was not called on one of the attribute conversions
Changes in the MetaDataMDX class to allow for entity id transformation.
Added support for endpoints as lists (read directly from JSON arrays instead of Python tuples) and UIInfo in SPSSO descriptor.
Also some cleanup of error message.
Merge pull request #168 from tpazderka/Fix_attribute_converters

Fixed attribute converters
Merge pull request #169 from its-dirg/saml_metadata_fix

Support for specifying endpoints as lists (instead of Python tuples) and UIInfo in SPSSO desc.
Tests will not fail if you don't have a MondoDB running.
Merge branch 'master' of github.com:rohe/pysaml2
pysaml2 needs at least pycrypto 2.2 for Crypto.RSA.importKey
Merge pull request #170 from erickt/pycrypto

pysaml2 needs at least pycrypto 2.2 for Crypto.RSA.importKey
Releasing new version.