Implement a much more capable vuprintf()

New support as well as some buggy support fixed.

Still no floating point support if ever that would be desired.

Support (*):
* Flags: '-', '+', ' ', '#', '0'

* Width and precision: 'n', '.n', '*' and '.*'

* Length modifiers: 'hh', 'h', 'j', 'l', 'll', 't', 'z'

* Radix: 'c', 'd', 'i', 'n', 'o', 'p/P', 's', 'u', 'x/X'

(*) Provision exists to switch lesser-used stuff on or off or when
certain functionality isn't desired (bootloader?). The compulsory
radixes are everything but 'o', 'n', 'p/P' and 'x/X' with length
modifiers being optional. The default setup is 'l', 'z', 'c', 'd',
'p/P', 's', 'u', 'x/X'.

* Move fdprintf() to its own file. It was in a strange place.

* Make callers compatible and fix a couple snprintf() bugs while
at it.

Could smush it down in size but I'm gonna get over the binsize
neurosis and just the let optimizer do its thing.

Change-Id: Ibdc613a9b6775802c188b29b9dd46c568c94f7c3

firmware/SOURCES

@@ -204,7 +204,7 @@ common/fileobj_mgr.c
 common/dircache.c
 #endif /* HAVE_DIRCACHE */
 common/pathfuncs.c
-common/format.c
+common/fdprintf.c
 common/linked_list.c
 common/strcasecmp.c
 common/strcasestr.c
@@ -214,6 +214,7 @@ common/strlcpy.c
 common/structec.c
 common/timefuncs.c
 common/unicode.c
+common/vuprintf.c
 
 /* Display */
 scroll_engine.c