Static build year

In a follow-on from gh-2173, the year shouldn't be completely dynamic, but rather generated at build time.

Testing in Python:
```
$ bin/omero shell
In [1]: from omero_version import build_year
In [2]: print build_year
2014
```

In the web, "© 2007-2014 University of Dundee & Open Microscopy Environment" should be shown.

@will-moore should be happy with the code.