Add script to create color fonts

Will eventually handle the proposal in
#3

tools/mkcolorfont.py

@@ -0,0 +1,41 @@
+from fontTools.ttLib import TTFont
+from fontTools.colorLib import builder as colr_builder
+import argparse
+
+argparser = argparse.ArgumentParser(description=
+    "Generate a color font from a given font where the color layer glyphs have a suffix .bg (background layer) and .fg (foreground layer).")
+argparser.add_argument(
+    'input',
+    help='Input font source, e.g. "/some/path/Bla.sfdir"')
+argparser.add_argument(
+    'output',
+    help='Output font file, e.g. "/some/path/Bla.otf"')
+args = argparser.parse_args()
+
+# Open the font file
+font = TTFont(args.input)
+
+# create two color palettes
+palette1 = [(0,0,0,1), (1,0,0,1)]
+palette2 = [(0.7,0.5,0.2,1), (0,0,1,1)]
+cpal=colr_builder.buildCPAL([palette1, palette2])
+
+
+font['CPAL'] = cpal
+
+# create the COLR table
+# Define the list of suffixes for the layer glyphs
+
+# Create a list of glyph names and corresponding layer glyph names
+glyphs = {}
+for glyph_name in font.getGlyphOrder():
+    if glyph_name.endswith(".bg"):
+        base_glyph_name, layer_suffix = glyph_name.rsplit(".", 1)
+        glyphs[base_glyph_name] = [(base_glyph_name  + "." + "bg", 0),(base_glyph_name + "." + "fg", 1)]
+colr_table = colr_builder.buildCOLR(glyphs)
+
+# add the COLR table to the font
+font['COLR'] = colr_table
+# Save the modified font file
+font.save(args.output)
+