ncurses: various bugfixes

ncurses: various bugfixes

 * Workaround KEY_END not working with $TERM=xterm on FreeBSD
 * Don't abort when printing strings with unprintable characters ( for example when the user presses ctrl+something in FIND or OPEN boxes )
 * Show a '*' in front of the current node
 * Add files in the correct node

This is how nodes do work in ncurses: When you select an item with 'Enter',

 * if it's a leaf, then start playing it, and set the current node to the toplevel parent of that leaf (example: local playlist, or media library)
 * if it's an empty node, then stop the playlist, and set the current node to be that one, so you can add items to it
 * if it's a node with children, set the current node to that one, and start playing the next children of that one

The "current node" means that the playlist will never reach items which aren't direct or indirect children of that node, and so it will stop after the last one has been reached