Run integration tests with different configurations

[pledbrook]

Different Lazybones configurations affect the behaviour of Lazybones (obviously). We should really be testing this different configurations. For example, I discovered that an empty configuration file broke the application with some exception being thrown.

This is really an extension of issue #69 and I think a system property containing the location of the configuration file should work fine.

[pledbrook]

The base implementation is done. Should still add a functional test for the empty configuration file.