minor format fixing
handle tuner control return status

don't disable tuner control when the initialization failed because of e.g.
connection problem. We should give it a second try
compare song information with stored line

it's unneccessary to fetch name and title from old mpd_song. Actually the
information is stored in the fline and sline buffer. Comparing the new song
information with the line buffers now. This way we can also fill the lines with
other information, while the content will be refreshed automatically.
improvement of printing screen

* fill the end of buffer with buildtime configurable fill patterns.
* Begin filling after printing the last character in the old buffer.
* don't scroll if line < 16