move functions around and some minor corrections
initial st_sprintf(char *out, const char *fmt, ...)
add a header for st_print Functions, they are a lot now
fixlet
move subnet_printf there
add generic st_fprint, st_sprintf, and st_printf functions
add header file for st_printf
add st_printf.h header where needed

Signed-off-by: etienne basset <etienne.basset@numericable.fr>