Thinner font, remove artifical spacing
Font: No tail for the 7

This is how my old clock radio does it. :-]
Show a full block for unknown characters
Fix nonsense
Multi-line rendering
Show years

Since we're breaking the string into two lines, we can now comfortably
show year information on an 80x25 terminal.
Remove useless type casts
Kick render_glyph_row()

It's just one for-loop, no need to put that into its own function. Also,
render_glyph_row() was only used in render_lines().
Tidying up a little bit