Added code to pull down and load GA4GH schemas in Python.
Changed update/modify time to input creation time.
Added support for Variant metadata.
Merge pull request #19 from fnothaft/import-schemas

Added code to pull down and load GA4GH schemas in Python.
Merge pull request #21 from jeromekelleher/v0.5.1

Update for v0.5.1
merged with 0.5.1; removed self.directory