Support for PostgreSQL functions when using Database First #150

   at System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition..ctor(DbProviderFactory storeProviderFactory, DbCommandTree commandTree, DbInterceptionContext interceptionContext, IDbDependencyResolver resolver, BridgeDataReaderFactory bridgeDataReaderFactory, ColumnMapFactory columnMapFactory)
   at System.Data.Entity.Core.EntityClient.EntityCommand.CreateCommandDefinition()
   at System.Data.Entity.Core.EntityClient.EntityCommand.TryGetEntityCommandDefinitionFromQueryCache(EntityCommandDefinition& entityCommandDefinition)
   at System.Data.Entity.Core.EntityClient.EntityCommand.GetCommandDefinition()
   at System.Data.Entity.Core.Objects.ObjectContext.CreateFunctionObjectResult[TElement](EntityCommand entityCommand, ReadOnlyCollection`1 entitySets, EdmType[] edmTypes, ExecutionOptions executionOptions)
   at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass161_0`1.<ExecuteFunction>b__1()
   at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
   at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass161_0`1.<ExecuteFunction>b__0()
   at System.Data.Entity.Infrastructure.DefaultExecutionStrategy.Execute[TResult](Func`1 operation)
   at System.Data.Entity.Core.Objects.ObjectContext.ExecuteFunction[TElement](String functionName, ExecutionOptions executionOptions, ObjectParameter[] parameters)
   at System.Data.Entity.Core.Objects.ObjectContext.ExecuteFunction[TElement](String functionName, MergeOption mergeOption, ObjectParameter[] parameters)
   at System.Data.Entity.Core.Objects.ObjectContext.ExecuteFunction[TElement](String functionName, ObjectParameter[] parameters)```