The Great Logging Refactor

Remove all instances of logger object being passed as parameters.
This was a holdover from ruffus, and complicated a lot of simple things.

tests/test_optimize.py

@@ -43,12 +43,7 @@ def test_mono_not_inverted(resources, outdir):
     opt.main(infile, outdir / 'out.pdf', level=3)
 
     rasterize_pdf(
-        outdir / 'out.pdf',
-        outdir / 'im.png',
-        xres=10,
-        yres=10,
-        raster_device='pnggray',
-        log=logging.getLogger(name='test_mono_not_inverted'),
+        outdir / 'out.pdf', outdir / 'im.png', xres=10, yres=10, raster_device='pnggray'
     )
 
     with Image.open(fspath(outdir / 'im.png')) as im: