remove the gui code from the DoAutoRecovery().

Instead, there is now an extended DoAutoRecovery function too which takes the function to
call after recovering a splinefont. That function takes a "SplineFont
*sf" arg which is the font that was recovered. This way the GUI code
can pass in a function that is called after each font recovery and the
non gui code (or python plugin, other app linking with libfontforge
etc), can enjoy not having those symbols.