Added Bounding Box, validation for all geometries, other changes.
Renames on result vars
Merge pull request #800 from lossyrob/feature-methods

WIP: Added Bounding Box, validation for all geometries, other changes to geotrellis-feature.
Parse feature as geometry to match the type
Avoid unwrapping until failure to match geom

A little cleaner this way
Merge pull request #803 from echeipesh/feature/geojson-polymorphism

Feature/geometry polymorphism in geojson