Modification to Equation of State / PVT Model WPC/Content Schema

The following attributes should be moved from the WPC to the Content Schema:

• EoSMethod
• ViscosityCorrelationMethod

The following units of measure need to be modified in our example units of measure

• Molecular Weight: lb/mol

The content schema is currently named 'eos_peng_robinson_lohrenz_schema' While this schema currently only directly covers the Peng-Robinson method of calculating an Equation of State, and the Lohrenz method of Viscosity Correlation, it will likely be expanded (at a later date in another issue) to accommodate other methods. To provide for this, we need to change the name to 'eos_content_schema'