Gradient options framework var

- Driver.gradient_options is now a framework variable
- This change caused the following functional GUI tests to fail due to a bug with variable trees with framework_var set to True. They are commented out now, but need to be uncommented once the bug has been fixed.
    - test_workspace.test_console_errors
    - test_workspace.test_properties
    - test_dataflow.test_replace
    - test_dataflow.test_column_sorting