font-patcher: Prevent autohinting on added symbols

[why]
The files sizes of otf files are (especially with the addition of the
current Material Design Icons) big enough already. The autohints are not
really useful for symbols, so we can drop them and save some space.

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

font-patcher

@@ -1055,6 +1055,7 @@ class font_patcher:
             self.sourceFont.selection.select(currentSourceFontGlyph)
             self.sourceFont.paste()
             self.sourceFont[currentSourceFontGlyph].glyphname = sym_glyph.glyphname
+            self.sourceFont[currentSourceFontGlyph].manualHints = True # No autohints for symbols
 
             # Prepare symbol glyph dimensions
             sym_dim = get_glyph_dimensions(self.sourceFont[currentSourceFontGlyph])