Merge pull request #609 from lossyrob/refactor/datasource

Fixed demo project
Fixes dev and geotools projects.
Merge pull request #610 from lossyrob/travis/update

Fixes dev and geotools projects.
Fixing tasks project
Merge pull request #611 from lossyrob/travis/update

Fixing tasks project
Add return type annotations to Zonal Summary Methods
Fix TiledPolygonalZonalSummarySpec to work with DataSource changes
Merge pull request #613 from ejc123/ZonalSummaryFix

Add return type annotations to Zonal Summary Methods
Merge pull request #614 from ejc123/FixZonalSummarySpec

Fix TiledPolygonalZonalSummarySpec to work with DataSource changes
Merge remote-tracking branch 'upstream/master' into refactor/datasource