Parameters of Patch modules can be changed in the config file

Fixes https://github.com/acq4/acq4/issues/5

Parameters of PatchWindow.params can now be changed by user
configuration. Unknown parameters or parameters that cannot
be converted to the proper data types are ignored

TODO: - replace plane 'print' by showMessage?
      - (re)move the type checking to make it more generic and
        usable in every module?