Spring MVC should server static resources (*.html, ...) located in src/main/webapp instead of returning "404 Not Found"

see: https://jira.springsource.org/browse/DATAJPA-292

Transactions should be on the root application context (or Hibernate will not be able to persist entities)

- integrated Gordon's comments in the POM
- removed antlr from the POM that we don't need anymore
- changed webjars versions inside headTag.jsp

Changed the birth date for all the pets (so we do not have a 12 year
old hamster where their life expectancy is 2-3 years :)  )

In that way we don't need a dedicated config file for the Service layer

see https://jira.springsource.org/browse/DATAJPA-292

(feedback from Oliver Gierke)