Add multiple segments support for AZTEC, CODEONE, DATAMATRIX, DOTCODE,

GRIDMATRIX, HANXIN, MAXICODE, MICROPDF417, PDF417, QRCODE, RMQR, ULTRA
RMQR: fix ECI encoding (wrong bit length for indicator)
MICROQR: check versions M1 and M2 for allowed characters so as to give
  better error messages
DOTCODE: some small optimizations
common.c: add is_chr(), segs_length(), segs_cpy()
CODEONE/CODE128/DOTCODE/GRIDMATRIX/HANXIN/MAXICODE/QRCODE/ULTRA: add
  namespace prefixes to static funcs/data
includes: use Z_ prefix, unuse double underscore prefixes (guard defines)
manual.txt: compress some tables using double/treble column sets

backend/general_field.h

@@ -1,6 +1,6 @@
 /*
     libzint - the open source barcode library
-    Copyright (C) 2019 - 2020 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2019-2022 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -27,10 +27,9 @@
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.
  */
-/* vim: set ts=4 sw=4 et : */
 
-#ifndef __GENERAL_FIELD_H
-#define __GENERAL_FIELD_H
+#ifndef Z_GENERAL_FIELD_H
+#define Z_GENERAL_FIELD_H
 
 #define NUMERIC         110
 #define ALPHANUMERIC    97
@@ -47,4 +46,5 @@ INTERNAL int general_field_encode(const char *general_field, const int general_f
 }
 #endif /* __cplusplus */
 
-#endif /* __GENERAL_FIELD_H */
+/* vim: set ts=4 sw=4 et : */
+#endif /* Z_GENERAL_FIELD_H */