Merge pull request #1114 from alxdarksage/units

Unit conversion utils.
PFLM-2619
PFLM-2619
PLFM-2619
PLFM-2619
PLFM-2619
Merge pull request #1120 from brucehoff/PLFM-2619

Plfm 2619
Unit conversion carried through the PD API/web services.
Merge branch 'develop' of https://github.com/Sage-Bionetworks/Synapse-Repository-Services into units