Set value for nil type for new mat export measures
Merge pull request #113 from jtferns/fix_missing_value

Set value for nil type when loading new MAT export measures.  This is needed because the new MAT HQMF exports do not always have a value on an expression.  This if for things like median and date difference.
updated cat3 export provider support, added cat3 provider template
Merge pull request #115 from projectcypress/cat3_provider_update

updated cat3 export provider support, added cat3 provider template
Updating Travis CI to test on Ruby 2.1.1 and removing develop testing
Releasing 3.4.3