Change default DHGRRGB tint back to 0 and update help message for

DHGRSHOW

src/dhgr.tk/utils/dhgrrgb.c

@@ -53,7 +53,7 @@ int phase[3] = {RED_PHASE_NTSC, GREEN_PHASE_NTSC, BLUE_PHASE_NTSC};
 int gammacorrect = 0; /* Gamma correction */
 int brightness   = 0;
 int saturation   = 255; /* 1.0 */
-int tint         = 22; /* imperically determined tint */
+int tint         = 0;  /* imperically determined tint */
 int orgmode;
 int errDiv       = 4;
 unsigned char rgbScanline[X_RES * 3]; /* RGB scanline */

src/dhgr.tk/utils/dhgrrgb.pla

@@ -101,7 +101,7 @@ var[3] phase   = RED_PHASE_NTSC, GREEN_PHASE_NTSC, BLUE_PHASE_NTSC
 byte gamma     = 0 // Gamma correction
 var brightness = 0
 var saturation = 255 // 1.0
-var tint       = 22 // = 45/2 deg
+var tint       = 0
 byte errDiv    = 4
 byte flags     = GREY_HACK
 var rgbErr // Running color error array

src/dhgr.tk/utils/dhgrshow.pla

@@ -158,5 +158,5 @@ if srccnt
   fin
   return retval
 fin
-puts("Usage: DHGRSHOW [-Z] <FILES>+\n")
+puts("Usage: DHGRSHOW [-Z] [-P#] <FILES>+\n")
 done