update license files to reflect addition of Arbor javascript libraries (used by visualization)
change kafka dependency scope to provided so users can choose whichever scala version they want
prep CHANGELOG for release 0.9.2-incubating
prepare for next development iteration
Revert "prepare for next development iteration"

This reverts commit c5e1e33db94da602ca5b57d04aa32599e9b90c35.
update maven-release-plugin to 2.5 (fixes issue where release fails to tag properly)