Redid unit display, also pep8 + pyflaked.

Unit display now keeps everything in the range 1.000-999.9, with 5 units
worth of magnitude (15 orders of magnitude).

u8unit has been replaced by f8unit and a helper function scaleforunit.

f8unit can optionally strip surrounding whitespace for cases such as 'rv'
where a compact display is required.

pylib/util.py and ntqq have been checked with pep8 and pyflakes to clean
up after previous neglect.