Satfinder / Automatic scan / Manual scan / Fastscan: Add
transponder scan to Satfinder plugin, add related visual
buttons for "OK"- and "Cancel"-functions to all above
(using default skin).

From pingflood: `Besides some minor cosmetics changes in
the code, the main new feature is that now you can start
scanning the transponder directly from the Satfinder. This
way you can find a satellite, fine tune it and scan the
current TP all from the same screen. In order to do this,
you just need to press "OK".'

Signed-off-by: Erik Slagter <erik@slagter.name>