REEF-43: Get version number from pom (via properties file)

This addresses https://issues.apache.org/jira/browse/REEF-43

The injectable class `Version` now gets the version number from pom (via a properties file).

I think the -incubating-SNAPSHOT is just as important as the 0.10. Also, trimming would require assumptions about the version format (e.g., that the short version is up to the first `-`) that I'm not too comfortable with.