URIManager: rename one instance variable
LoadingConfigurationBuilder: fix default parser features...

It is _not_ EnumSet.noneOf(JsonParser.Feature.class). Unfortunately, Jackson
right now makes this exceedingly difficult to collect the default features since
it returns them as an integer :/
URIManagerTest: write a test which succeeds whereas I thought it would fail...

Given that the user attempts to remove stream autoclose, I'd have expected the
source _not_ to be closed... Or maybe I misunderstand how it works.
Try and fix the undefined sonatype{Username,Password} problem again %)