Do not automatically convert Python strings to Octave strings (fixes issue #65) * python_to_octave.cc (pytave::pyobj_to_octvalue): Drop conversion of bytes and unicode objects. * __py_struct_from_dict__.cc (F__py_string_value__): New function. * @pyobject/char.m: Define outside class definition, use __py_string_value__. * @pyobject/pyobject.m: Delete previous pyobject.char definition. * @pyobject/methods.m: Apply char conversion to __name__ attribute. * @py/py.m, @pyobject/cell.m, @pyobject/dummy.m, @pyobject/subsasgn.m, @pyobject/subsref.m, pyargs.m, pycall.cc, pyeval.cc: Adapt examples and tests to changes.