Merge pull request #68 from chuckdumont/master

Fix intermittent last-modified failure in LayerTest
Latest version of m2e throws exceptions if child poms do not have 
lifecycle mapping versions specified.
Use static imports for Assert methods.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	jaggr-service/src/test/java/com/ibm/jaggr/service/impl/layer/LayerTest.java
Fix for issue #69 (NPEs when serializing cache)