Default refresh to True (ebuild)

See #3302
Make both "refresh=true" and "refresh=True" work

Also pep8 fixes.
Default refresh to True (pkgutil) + pep8 fixes

See #3302
Add refresh param + pep8 fixes

list_upgrades and upgrade are not yet implemented, but I added some
commented-out bits that can be uncommented once these functions are
implemented.
Default refresh to True (yumpkg) + pep8 fixes

See #3302
Prevent traceback using refresh param

Make the same change as was made in f0d1043 to pacman.py
Default refresh to True (zypper) + pep8 fixes

See #3302
Default refresh to True (yumpkg5) + pep8 fixes

See #3302
Fix Ubuntu bug in pkg.purged, pkg.removed states

17e35529 introduced a bug in which a nonexistant kwargs dict was being
referenced in the pkg.purge and pkg.remove functions. This is a blocker
for pkg.purged and pkg.removed states in Ubuntu.

I added kwargs to the pkg.purged and pkg.removed states, as well as to
each pkg provider which had a purge or remove function.

Note that this commit contains a lot of the same pep8 fixes that I made
in pull request #3311, so let me know if you want me to rebase once this
is merged.