We don't currently support rendering SVG glyphs so they should be
ignored when loading. Additionally, the check for whether a glyph is
colored has been simplified by just checking the pixel mode of the
rendered bitmap.
This commit also fixes a bug caused by calling the color check inside of
`renderGlyph`, which caused the bitmap to be freed creating a chance for
memory corruption and garbled glyphs.
6f84a5d682