prepare release.

M
Merge pull request #12 from msimonin/maint-2.1.0

fix javadoc
Merge branch 'maint-2.1.0' of https://github.com/snoozesoftware/snoozeec2 into maint-2.1.0
add changelog.
update release-plugin version.

M
[maven-release-plugin] prepare for next development iteration
post release (deb package)
M