Use jgit-buildnumber to set version information in Maven

This is more or less the Maven equivalent of gh-627.

Overriding with ```omero.version``` is not supported from Maven, but hard-coded version numbers have been removed and are instead set using https://github.com/alx3apps/jgit-buildnumber and http://docs.codehaus.org/display/GMAVEN/Home.  This includes the version numbers in ```components/scifio/cppwrap/*.cpp```.

Running ```mvn -DskipTests``` and then running this snippet with ```components/loci-tools/target/loci_tools*.jar``` should print out meaningful version information:

```
System.out.println(FormatTools.DATE);
System.out.println(FormatTools.VERSION);
System.out.println(FormatTools.VCS_REVISION);
```