#84 Wrong song info in File Info dialogue when no song loaded

[quanta]

When using plugin to load a song or when an existing song is unloaded, the Format field in File Info dialogue box incorrectly shows the file format of the song being loaded as eXtra Simple Music[1]. Instrument list actully shows list of instruments instead of empty[1]. In the Info box, it incorrectly shows Order, Pattern, Row, Speed, Timer fields as 0 / 0, 0 / 0, 0, 0, 5.00[1] Hz repsectively. In the Subsong area, it incorrectly shows first and last song numbers as 1.

Since there is no active song, Format field and instrument list should be empty. In addition, the plugin already uses number 0 for Order, Pattern, Row, Speed fields for a loaded song, it confuses users into thinking a song is loaded where it is not, so those fields should be empty. Similarly, timer field should be empty. When there is no active song, there should be no first and last song numbers in the Subsong box, and the slider should be disabled.

[1] The actual values vary depending on the file formats of the songs previously loaded within a music player session, but none of the values are correct.