Fix imports; run tests with packaged dependencies

Tests are currently run with a classpath containing all downloaded jars. The tests would be more reflective of the behavior of a runtime environment if the test classpath only contained jars that are bundled with the binary release, together with explicit test dependencies. Ideally we'd use the build/lib/ jars for the classpath since that's what gets packaged, but since these aren't available at test compile time and should be identical to lib/ anyway, I've used the later.

Doing so exposed a couple of references in src/java to "org.apache.commons.lang", which is not available at runtime (should be "org.apache.commons.lang*3*").

Attached patch modifies the test classpath, fixes various imports in both test/ and src/ classes, and makes some simple substitutions in the tests such as using AbstractMap.SimpleEntry in place of org.apache.commons.collections.keyvalue.AbstractMapEntry.