Implemented back the Mask mode. Fixed a historical bug of memory violation if you used Mask with images of different sizes (would crash all platforms except DOS)

git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@1237 416bcca6-2ee7-4201-b75f-2eb2f807beb1

misc.h

@@ -30,6 +30,7 @@
 #define SWAP_DWORDS(a,b) { dword c=a; a=b; b=c;}
 #define SWAP_SHORTS(a,b) { short c=a; a=b; b=c;}
 #define SWAP_FLOATS(a,b) { float c=a; a=b; b=c;}
+#define SWAP_PBYTES(a,b) { byte * c=a; a=b; b=c;}
 
 void Copy_image_to_brush(short start_x,short start_y,short Brush_width,short Brush_height,word image_width);
 void Remap_general_lowlevel(byte * conversion_table,byte * buffer,short width,short height,short buffer_width);