Re-add siesta + siesta-test plugins
Merge branch 'move-rest-api-to-plugin' into siesta-plugin2

Conflicts:
	nexus/nexus-core-plugins/pom.xml
Merge branch 'move-rest-api-to-plugin' into siesta-plugin2

Conflicts:
	nexus/nexus-core-plugins/pom.xml
Merge branch 'move-rest-api-to-plugin' into siesta-plugin2
update for upstream changes
Merge branch 'move-rest-api-to-plugin' into siesta-plugin2
Merge branch 'master' into siesta-plugin2
Move to plugins directory
Squash-o-matic output

Changes:
* modules removed: nexus-utils, nexus-api, nexus-configuration, nexus-proxy, nexus-app, nexus-plugin-manager
* module "cleaned": nexus-configuration-model, now holds only modello models. Remains to be reusable (for some CLI tools)
* module nexus-core introduced, that is actually The Core of Nexus
UTs fixed
Removed all "perf" tests, as they made no sense.

Perftests for AttributeStorage was "perf" testing 3 implementations,
2 of them were totally unused (map one?) and irrelevant. The whole test
made no sense, as they were implemented at the time of Nx 2.0 when
we wanted to choose the tech that will supersede the XStream backed
one.

Same for LocalStorage, as the two test had no substantial difference,
and they were meant to catch attribute handling related problems, such
as slowdowns. Back then, there were no load tests, or any other kind
of real perf tests, so I removed them too.

Both set of tests were a muddy mixture of mocks, trickeries and such,
making the PITA to fix them, while again, their value is questionable.
Merge remote-tracking branch 'origin/master' into squash-o-matic-output

Conflicts:
	nexus/nexus-api/pom.xml
	nexus/nexus-app/pom.xml
	nexus/nexus-plugin-test-api/pom.xml
	nexus/nexus-utils/pom.xml
	nexus/plugins/restlet1x/nexus-restlet1x-plugin/pom.xml
Merge remote-tracking branch 'origin/master' into squash-o-matic-output
Moved new file in it's propr place
Commons IO slipped out

Chjange from master
Some ITs needs Nexus internals.

But after cleanup, the edition was not coming anymore to the IT
classpath. Explicitly adding it.
Merge branch 'master' into squash-o-matic-output
Merge branch 'master' into siesta-plugin2
update headers
Updated to newer version of compiler plugin