Add a reader and createSystem interface for Desmond dms files
Simpler use of quantity
reorder the exclusion before the pair_12_6_es_term so simplify code
Ignore constraints that connect two massless particles (feature request 1915)
intermediate commit, work on virtualsites
Implement virtualsites and better checking of unsupported params/tables
Fixed bug in previous commit
Add provenance
Merge pull request #154 from rmcgibbo/dms

Create system from Desmond files
Merge pull request #155 from peastman/master

Ignore constraints that connect two massless particles (feature request 1915)
Added unittest and 1 system tests. Includes 1 bugfix to resolving a circular import and 1 bugfix where dms wasn't creating the topology correctly when the water was specified in different chains
Bugfix: dms.positions should be a Quantity(list(Vec3)), not a list(Quantity(Vec3))
typo: extra s
same fix about list(quantity) vs quantity(list) for unitcell dimensions
Fix to PR #152
Merge pull request #158 from rmcgibbo/pdbbug-bugfix

Fix to PR #152
Merge pull request #156 from rmcgibbo/dmstests

dmstests
Python records where OpenMM is installed, so it doesn't need to be specified with environment variables at runtime
Created reference implementation of SETTLE
Merge pull request #161 from peastman/master

Created reference implementation of SETTLE