Fix incorrect border colours

src/scripts/Profiles/6BIT_YUV_Analog/Dragon.txt

@@ -2,3 +2,4 @@ sampling=2,1,1,1,0,0,2,8,0,29,23,133,95,40,100,0,35
 geometry=76,54,272,208,320,240,1,1,3,8,7159090,456,5000,312,2,0,0
 palette=Dragon-CoCo_Full
 output_invert=2
+border_colour=3

src/scripts/Profiles/6BIT_YUV_Analog/Spectrum_48K.txt

@@ -2,3 +2,4 @@ sampling=7,1,1,0,1,1,2,8,0,108,65,176,125,255,230,0,150
 geometry=68,54,272,200,384,288,1,1,3,8,7000000,448,5000,312,5,0,0
 palette=Spectrum_48K_9Col
 output_invert=2
+border_colour=3

src/scripts/Profiles/6BIT_YUV_Analog/Tandy_CoCo_PAL.txt

@@ -2,3 +2,4 @@ sampling=13,1,1,1,0,0,2,8,0,64,54,133,95,84,100,0,75
 geometry=72,54,272,208,320,240,1,1,3,8,7119090,456,5000,312,3,0,0
 palette=Dragon-CoCo_Full
 output_invert=2
+border_colour=3