Add new BC for variable densities in pressure FLOW_PRESSURE_VAR
Merge pull request #62 from dshari/FLOW_HYDROSTATIC_NEW

Add new BC for specifying hydrostatic pressure FLOW_HYDROSTATIC_NEW
Added entry for FLOW_PRESSURE_VAR to CHANGELOG
Merge pull request #63 from dshari/FLOW_HYDROSTATIC_NEW

Added entry for FLOW_PRESSURE_VAR to CHANGELOG