[devel] Implemented remaining "_fixed" functions and corrected warnings

that were recently introduced, mostly resulting from
safe but uncast assignments to shorter integers.  Also added a zlib
VStudio release library project because the latest zlib Official Windows
build does not include such a thing.

scripts/pnglibconf.dfa

@@ -6,7 +6,7 @@
 #
 com pnglibconf.h - library build configuration
 com
-com libpng version PNGLIB_VERSION - last changed on July 30, 2010
+com libpng version PNGLIB_VERSION - last changed on July 31, 2010
 com
 com Copyright (c) 1998-2010 Glenn Randers-Pehrson
 com
@@ -338,7 +338,7 @@ option WRITE_INTERLACING requires WRITE
 
 # The following depends, internally, on WEIGHT_SHIFT and COST_SHIFT
 # where are set below.
-option WRITE_WEIGHTED_FILTER requires WRITE FLOATING_POINT
+option WRITE_WEIGHTED_FILTER requires WRITE
 
 option WRITE_FLUSH requires WRITE
 

scripts/pngwin.def

@@ -218,11 +218,11 @@ EXPORTS
  png_save_int_32 @206
  png_save_uint_16 @207
  png_set_gamma_fixed @208
-; png_set_filter_heuristics_fixed @209
-; png_get_pixel_aspect_ratio_fixed @210
+ png_set_filter_heuristics_fixed @209
+ png_get_pixel_aspect_ratio_fixed @210
  png_get_x_offset_inches_fixed @211
  png_get_y_offset_inches_fixed @212
-; png_set_sCAL_fixed @213
+ png_set_sCAL_fixed @213
  png_get_sCAL_fixed @214
  png_get_num_passes @215
  png_get_num_rows @216

scripts/symbols.def

@@ -214,11 +214,11 @@ EXPORTS
  png_save_int_32 @206
  png_save_uint_16 @207
  png_set_gamma_fixed @208
-; png_set_filter_heuristics_fixed @209
-; png_get_pixel_aspect_ratio_fixed @210
+ png_set_filter_heuristics_fixed @209
+ png_get_pixel_aspect_ratio_fixed @210
  png_get_x_offset_inches_fixed @211
  png_get_y_offset_inches_fixed @212
-; png_set_sCAL_fixed @213
+ png_set_sCAL_fixed @213
  png_get_sCAL_fixed @214
  png_get_num_passes @215
  png_get_num_rows @216