Checkstyle violations

Wired checkstyle into maven, and fixed current violations.  Checkstyle is currently breaking over the lambda in YearQuarter.java, which is a known error (with a fix in the works).
The default reporting location is putting some files into the base target directory, not sure if that should be changed (should be .pom entries).
Currently only wired up as reporting, not into the build (which would allow failing the build for violations).