checksum_type not returned
Adding tracking_id proprty
Beginning to implement ESGF manifests.
Making an import local to avoid circular references
Implemented manifest generation direct from SOLr
Functional entry point for extracting manifests from SOLr
Simple command-line entry point for extract from SOLr
Refining SOLr extract to manifest implementation
Support minimum timestamp for SOLr extract
Added code to interact with the SAML Attribute Service.
Added a test for the AttributeService client and fixed some issues.
Extra AttributeService test
Significantly simplified SAML Attribute handling.

It turns out that the ESGF AttributeService doesn't use the groupRole type any more.
Attributes are just name/value pairs so we can do away with FriendlyName and URNs.
Support attributes with multiple values
Added convenience class for deducing service endpoints
Reorganising
Added issuer parameter to AttributeService suggested by Prashanth
Merge branch 'devel'
bump version to v0.1.2