Improvements to geometric glyphs (additions and changes)

New glyphs:
- blackSquare                (U+25A0)
- whiteSquare                (U+25A1)
- whiteRoundedCornersSquare  (U+25A2)
- lowerHalfWhiteSquare       (U+2B12)
- topHalfWhiteSquare         (U+2B13)
- downWhiteTriangle          (U+25BD)
- upWhiteTriangle            (U+25B3)
- leftWhiteTriangle          (U+25C1, U+25C5)
- rightWhiteTriangle         (U+25B7, U+25BB)

Updated glyphs:

- triagdn                    (U+25BC)
- triagup                    (U+25B2)
- blackleftpointingtriangle  (U+25C0, 25C4)
- triagrt                    (U+25BA, 25B6)
- heartWhiteSuit             (U+2661)
- circlewhite                (U+25CB)