Added glyph preview column to the SVG font editor.
Added glyph view mode as an alternative to the list.
Added "edit" button to switch to the layer with the same label as glyph name. This can facilitate glyph editing. If layer is missing, it will be inserted.
Glyph creation now does not name glyphs by default. The new column "unicode" shows unicodes of characters that glyph is mapped to.