Issue 8 remove database configuration

This merge request sediments what we have discussed along the week. Basically I removed bob.bio.db package and move the BioDatabase and BioFile classes to bob.bio.base. I will branch the bob.nightlies to better do the integration tests.

I will leave this merge request open, just to not forget

bob/bio/base/database/__init__.py

+from .file import BioFile
+from .file import BioFileSet
+from .database import BioDatabase
+from .database import ZTBioDatabase
+
+# gets sphinx autodoc done right - don't remove it
+__all__ = [_ for _ in dir() if not _.startswith('_')]