Several cleanups from Manuel Novoa III.

get_kernel_revision --  size reduction
        NOTE: may want to combine with get_kernel_version in insmod???

parse_mode -- size reduction, multiple settings with "," now work correctly,
        sticky-bit setting now implemented

process_escape_sequence -- size reduction, octal code to big for char bug fixed

format -- size reduction, val > LONG_MAX and hr = 1 printing bug fixed (was %ld),

include/busybox.h

@@ -232,7 +232,7 @@ extern int sysinfo (struct sysinfo* info);
 #endif
 
 #ifdef BB_FEATURE_HUMAN_READABLE
-char *format(unsigned long val, unsigned long hr);
+const char *format(unsigned long val, unsigned long hr);
 #define KILOBYTE 1024
 #define MEGABYTE (KILOBYTE*1024)
 #define GIGABYTE (MEGABYTE*1024)