Adds hydrogen bond constraints. Updates contents to SMIRNOFF 0.3 spec (spec change performed by OFF toolkit 0.4.0 reading smirnoff99Frosst-1.0.9, and then writing the ForceField object out in the 0.3 spec). Fixes several issues with FF hierarchy, SMIRKS patterns. This fixes some issues with coverage of certain areas of chemical space, and parameters which could never be utilized due to hierarchy issues. Full details available in openforcefield/openforcefield Issue 367.