- zint_symbol->fgcolour & bgcolour buffer lengths extended 10

-> 16 to allow for "C,M,Y,K" comma-separated decimal percentage
  strings
- API/CLI/GUI: allow foreground/background colours to be specified
  as comma-separated decimal "C,M,Y,K" strings where "C", "M" etc.
  are percentages (0-100) (ticket #281, 3rd point)
- output.c: new funcs `out_colour_get_rgb()` & `out_colour_get_cmyk()`
  and use in bmp/emf/gif etc.
- PCX: add alpha support
- GUI: fix fg/gbcolor icon background not being reset on zap
- GUI: Rearrange some Appearance tab inputs (Border Type <-> Width,
  Show Text <-> Font, Text/Font <-> Printing Scale/Size) to flow
  more naturally (hopefully)
- GUI: save button "Save As..." -> "Save..." and add icon
- CLI: add --bgcolor/colour & --fgcolor/colour synonyms

docs/zint.1

@@ -72,8 +72,9 @@ starting with \[lq]00001.png\[rq], \[lq]00002.png\[rq] etc., which can
 be changed by using the \f[V]-o\f[R] | \f[V]--output\f[R] option.
 .TP
 \f[V]--bg=COLOUR\f[R]
-Specify a background (paper) colour where \f[I]COLOUR\f[R] is in hex
-\f[V]RRGGBB\f[R] or \f[V]RRGGBBAA\f[R] format.
+Specify a background (paper) colour where \f[I]COLOUR\f[R] is in
+hexadecimal \f[V]RRGGBB\f[R] or \f[V]RRGGBBAA\f[R] format or in decimal
+\f[V]C,M,Y,K\f[R] percentages format.
 .TP
 \f[V]--binary\f[R]
 Treat input data as raw 8-bit binary data instead of the default UTF-8.
@@ -211,8 +212,9 @@ Use faster if less optimal encodation or other shortcuts (affects Data
 Matrix, MicroPDF417, PDF417, QRCODE & UPNQR only).
 .TP
 \f[V]--fg=COLOUR\f[R]
-Specify a foreground (ink) colour where \f[I]COLOUR\f[R] is in hex
-\f[V]RRGGBB\f[R] or \f[V]RRGGBBAA\f[R] format.
+Specify a foreground (ink) colour where \f[I]COLOUR\f[R] is in
+hexadecimal \f[V]RRGGBB\f[R] or \f[V]RRGGBBAA\f[R] format or in decimal
+\f[V]C,M,Y,K\f[R] percentages format.
 .TP
 \f[V]--filetype=TYPE\f[R]
 Set the output file type to \f[I]TYPE\f[R], which is one of