Removed Requires module and replaced it with a set of more idiomatic operators (i.e.: 'Requires.ArgumentSatisfies condition "argName" "description"' is replaced by 'invalidArg condition "argName" "description"')
Added StateExpression function to LTL; added missing LTL functions to F# project
Renamed SubcomponentSymbol to ComponentReferenceSymbol; added symbols and symbol-to-object mappings to ModelSymbol and ModelObject; FieldAccessExpression now has optional symbol for referenced component