- CODABLOCKF: fix misencodation of extended ASCII 0xB0-0xB9 when

followed by digit (ignore 2nd byte of FNC4 when categorizing
  Code C characters)
- New `ZBarcode_Cap()` flag `ZINT_CAP_BINDABLE`, differentiated
  from `ZINT_CAP_STACKABLE`, and new Qt Backend method
  `isBindable()`
- CLI: fix `separator` check to use new `ZINT_CAP_BINDABLE` instead
  of `ZINT_CAP_STACKABLE`
- ZBarcode_Cap: add missing symbologies to `ZINT_CAP_BINDABLE` (was
  `ZINT_CAP_STACKABLE`)
- DOTCODE: pad rows if given number of columns instead of failing
  if rows below min (5)
- DBAR/composites: ensure stacked symbologies and composites are
  not stacked (set `symbol->rows` to 0)
- test suite: move `test_perf` routines into single test
  "test_perf";
  new "test_random" (based on "test_bwipp") to test various
  symbologies with random binary - discovered CODABLOCKF bug;
  expand "test_bwipp"
manual: Feeback: mention AZTEC -1 meaning min & MICROPDF417:
  doc new `ZINT_CAP_BINDABLE`
general: various code fiddlings and re-formattings

backend/common.h

@@ -206,7 +206,6 @@ INTERNAL int posn(const char set_string[], const char data);
   `bin_posn`. Returns `bin_posn` + `length` */
 INTERNAL int bin_append_posn(const int arg, const int length, char *binary, const int bin_posn);
 
-
 #define Z_COMMON_INLINE   1
 
 #ifdef Z_COMMON_INLINE
@@ -267,7 +266,7 @@ INTERNAL int errtxt_adj(const int error_number, struct zint_symbol *symbol, cons
 
 
 /* Whether `symbology` can have row binding */
-INTERNAL int is_stackable(const int symbology);
+INTERNAL int is_bindable(const int symbology);
 
 /* Whether `symbology` is EAN/UPC */
 INTERNAL int is_upcean(const int symbology);