Merge pull request Sage-Bionetworks#540 from Sage-Bionetworks/develop

release 1.8.1 develop to master

Merge pull request Sage-Bionetworks#534 from Sage-Bionetworks/develop

release 1.8.0 to master

Merge pull request Sage-Bionetworks#509 from zimingd/release-175

rolled version to 1.7.5

Merge pull request Sage-Bionetworks#506 from Sage-Bionetworks/develop

1.7.4 Release to master

Revert "Row and PartialRow now always cast values to string (SYNPY-61…

…5) (Sage-Bionetworks#497)" (Sage-Bionetworks#498)

This reverts commit ad9626e.

Update release-1.7.1.md