SAMZA-495; upgrade to 0.8.0 samza

Conflicts:
	pom.xml
	samza-wikipedia/pom.xml
FIXUP: build on latest coast / samza 0.8.0

Mostly superficial changes, which is a good sign.
Update README.md

Pull coast-related stuff above the fold
Link directly to the coast jobs
Update README.md

Add warning about stale code.
Update README to point to the latest docs / remove warning
Merge into existing hello-coast branch