Remove the *_set_res() function entirely. Instead, the *_resize() function now
accepts a height argument which is used as quality hint. Internally, we compute
the texture width by the selected font plus the given height. This simplifies
the API and the internal handling and improves output on non-standard
resolutions or with non-standard fonts.
Until now it was only optimized for my 16x9 output but 5x4 output was quite
garbled.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>