Move scalang to latest overlock library.

Upgrade scalang to track the latest overlock library. Remove usage of
log4j based logger - switch to slf4j based logula port.
Merge pull request #34 from pkwarren/latest_overlock

Move scalang to latest overlock library.
[maven-release-plugin] prepare release scalang-scala_2.9.1-0.28
[maven-release-plugin] prepare for next development iteration
Update dependencies, move to Java 7.