Adds cut, copy, paste and delete to GlyphEditor. Font preview has
moved to a separate resizable ToolWindow. Font metadata can now be
hidden. FontEditor and glyph widgets can now be re-initialized
instead of resetting window's main widget after loading new fonts.
This adds a new structure 'Typeface' to the FontDatabase that
represents all fonts of the same family and variant.
It can contain a list of BitmapFonts with varying size but of
the same family and weight or a pointer to a single TTF font
for all sizes of this Typeface.
