- raster/BMP/GIF/PCX/TIF: fix dealing with very large data (use

`size_t` as appropriate)
- BMP: lessen heap memory usage by only `malloc()`ing a row, not
  whole file
- GIF: lessen heap memory usage by paging (also simplifies some
  function returns); use standard colour char map
- raster: add `raster_malloc()` to fail > 1GB (avoids very large
  output files that most systems can't handle; also lessens to
  some degree chances of being victim of OOM killer on Linux)
- GUI: printing scale dialog: set maxima on X-dim and resolution
  to keep scale <= 200

backend/tests/data/print/eps/code128_aim.eps

@@ -1,5 +1,5 @@
 %!PS-Adobe-3.0 EPSF-3.0
-%%Creator: Zint 2.12.0.9
+%%Creator: Zint 2.13.0.9
 %%Title: Zint Generated Symbol
 %%Pages: 0
 %%BoundingBox: 0 0 136 117

backend/tests/data/print/eps/qr_v1_m.eps

@@ -1,5 +1,5 @@
 %!PS-Adobe-3.0 EPSF-3.0
-%%Creator: Zint 2.12.0.9
+%%Creator: Zint 2.13.0.9
 %%Title: Zint Generated Symbol
 %%Pages: 0
 %%BoundingBox: 0 0 42 42

backend/tests/data/print/eps/ultracode_a.eps

@@ -1,5 +1,5 @@
 %!PS-Adobe-3.0 EPSF-3.0
-%%Creator: Zint 2.12.0.9
+%%Creator: Zint 2.13.0.9
 %%Title: Zint Generated Symbol
 %%Pages: 0
 %%BoundingBox: 0 0 26 26