Fix NginxController's use of LinkedHashMultimap

- Don't call private constructor, which has been deleted in
  guava 13.
default deployment is now to filesystem on cloudfronted developers-origin,
with profile for deploying to artifactory;
docs updated to show same (new) preferred download URLs

(cherrypicked from master)
fix docs build for the case where we are building docs for the root
(backport cherry-pick from master)
brooklyn-dist should be in a directory named for the current version, not hanging off the root
(backport cherry-pick from master)
update download links and instructions to reflect dist archive structure,
and be a little bit clearer in general
(backport cherry-picked from master)
pom updated to support deployment to sonatype
(backport cherry-pick from master)
remove unused sections of pom
(backport cherry-pick from master)
reorder profiles in pom (no changes)
(backport cherry-pick from master)
created bogus empty java files for examples, so that javadoc artifact is created, and build is not rejected by maven central!
(cherry-picked from master)
doc links updated to point at sonatype and maven central (in addition to cloudsoft)
(backport cherrypicked from master)