Re-include flag for enabling jacoco unit test coverage reporting on fcrepo-kernel-impl

Follow-on resolution for: https://www.pivotaltracker.com/story/show/77197212
Upgrade modeshape version to 4.0.0.Beta1

Resolves: https://www.pivotaltracker.com/story/show/77806922
Update jacoco dependency to support java 8
fix javadoc tags to be syntactically valid
Update to powermock 1.5.5 for java 8 compatibility
Merge pull request #446 from fcrepo4/jdk8

Update jacoco dependency to support java 8
Code with @Before mock failure
Remove the statics
changed RegistryService to singleton
Added test for ReporterFactory (metrics). Removed static from declaration of RegistryService (metrics). Modified accordingly classes calling static getMetrics() in fcrepo-kernel
removed spurious build.out reports
merged conflicts