Merge pull request azavea#530 from azavea/rde/version/0.8.1

Version 0.8.1

Fix typos in docs.

Merge pull request azavea#209 from azavea/lf/rv1-parallel

Add parallel prediction for old version of object detection

This tag is for the final commit where we were working on

semantic segmentation and tagging. Since then, we have switched
our focus to object detection and don't want to have to maintain
the segmentation and tagging code, so we are removing that. At
some point in the future, this functionality may be resurrected and
refactored.