Removed unused reference and injected Nexus.
Removed Nexus.

As actually not nexus but AppStatus is needed here.
Deprecated all of Nexus god object.
Removed last non-boot related bits from DefaultNexus.
Stop using Nexus god object.
Merge remote-tracking branch 'origin/master' into remove-god-object
Adapted test to changes
Removed all uses of Nexus and DEfaultNexus.

Introduced NxApplication component that is
lifecycle and takes care about boot process.
Deadlock fix.

In this test the old Nexus component was implicitly looked
up -- hence Nx started -- as Resources did pull it in.

Since changes, now explicit start of Nx needed, otherwise
the waitForRoutingBackgroundUpdates() causes infinite
wait, since they did not even start.
Merge pull request #141 from sonatype/remove-god-object

NEXUS-5884 Remove use of Nexus god object