CHANGE_COLOR palette option adjustments

It was too early to call the windowport change_color() routine
while processing the config file. The windowport was not yet
fully operational.

Now the palette option processing will just place the rgb
value into the appropriate ga.altpalette[CLR_MAX] entry.

init_sound_disp_gamewindows(void) [allmain.c] calls
change_palette() [coloratt.c] and it will call the windowport
change_color() function for each ga.altpalette[] entry that
has been set.

Notes:
The rgb values stored in ga.altpalette[] have the NH_ALTPALETTE bit set
so that the rgb value of 0 can be stored and be distinguishable from
a "not set" entry.

The NH_ALTPALETTE bit is cleared from the rgb value in change_palette()
prior to calling the windowport change_color() function.

The syntax for palette is colorname/r-g-b.
For example: palette:black/12-12-12

colorname must be one of the NH_BASIC_COLOR names or a suitable
alias for one of those 16 entries.

Some of the windowport CHANGE_COLOR functions had the wrong parameters,
perhaps due to bitrot. Those have been corrected to match the prototype.

include/color.h

@@ -55,6 +55,7 @@
 #define HI_ZAP CLR_BRIGHT_BLUE
 
 #define NH_BASIC_COLOR  0x1000000
+#define NH_ALTPALETTE   0x2000000
 #define COLORVAL(x) ((x) & 0xFFFFFF)
 
 enum nhcolortype { no_color, nh_color, rgb_color };