The backend runs its own sound thread anyway,
with the corresponding bookkeeping that we use.
We don't need yet another sound thread,
and it is always nice to not have something
that could change our structures from underneath us.
This is a first step towards getting rid of all uses of regular printf,
fprintf, vprintf, vfprintf, puts, fputs, etc. in our codebase.
The name format() reflects the purpose of the function, and parallels
String.format() in Java, boost::format, and others.
svn-id: r54004
