Merge pull request #31 from ldecicco-USGS/master

Troubleshooting merge ref issues.
Merge pull request #32 from ldecicco-USGS/master

Update README.md
Merge pull request #33 from ldecicco-USGS/master

Fixed unit data examples.
Fixed a spelling mistake.
Merge branch 'master' of github.com:USGS-R/dataRetrieval