Stop requiring editing of example scripts

The example scripts include hardcoded values that
do not work for everyone. Instead of requiring the
files to be edited (and dirtying the git tree),
allow them to take command-line arguments.

Also adds better guidance for Mac OSX virtual
serial ports.

Scan/STLcd/bitmap2Struct.py

@@ -110,7 +110,10 @@ class STLcdGraphic:
 		return display
 
 
-filename = "ic_logo_lcd.bmp"
+filename = sys.argv[1]
+if filename is None:
+	print( "You must specify a bitmap filename. Try './bitmap2Struct.py ic_logo_lcd.bmp'" )
+	sys.exit( 1 )
 max_height = 32
 max_width = 128
 x_offset = 0