keepalive: attempt to fix issue1003 This is a reimport of the relevant piece of the upstream urlgrabber, which appears to be more correct.

test-archive: silence stupid messages from GNU tar Recent versions of GNU tar have apparently decided they're old enough that it's ok for them to prattle on senselessly about things no one cares about without anyone objecting. We object; apply duct tape.

ui: introduce new config parser

ui: simplify init, kill dupconfig

ui: fold readsections into readconfig readconfig now reads only single files readconfig takes an optional list of sections readconfig trusts files we're looking for sections in

ui: cleanup _is_trusted a bit

ui: simplify parent overlay logic

ui: always have ucdata simplify readconfig logic

ui: fold verbosity_constraints into fixconfig, simplify

ui: kill updateopts Move setconfig into dispatch._parseconfig

ui: refactor option setting No more passing options as constructor keywords. Basic options are now always stored in the overlay for simplicity and consistency.

ui: kill redundant call to verbosity_constraints

ui: always have an overlay

ui: kill check_trusted

ui: move _isatty near user