Change songmenu navigation help.
Fix missing first syllable bug. Re-enable flashing cover in songs screen.

- Quickly hacked forced full loading together with hacky way of skipping headers caused the first line of TXT notes to be skipped
- Notes of the currently chosen song need to be loaded (now with NULL-check to avoid crash)
- Cover is flashing in menu position 1 (cover browser), not in 0 (playlist)
- Needs more testing; the song parsing / note dropping and all of that is too full of hacks...
Display current playlist on song selector. Flashing when selected. 3D for stereo3d.

- Increased cached covers count to 50 so that things don't get broken so quickly
- The number of songs on playlist, or at least the number of those covers rendered, needs to be limited to about 30
Rework playlist navigation.

- Songs are added without popup menu
- Playlist is not cleared even when exiting the song browser
- Jukebox adds current song and starts playback on start (it was broken, didn't do anything)
- Quiting song returns to song browser (rest of the playlist is preserved)
- Selection is always returned to cover browser after playlist menu actions