[sql] preprocess_entity uses lgdb helper's SQL converters. The preprocess_entity does not yield anymore the conversion logic for different base types, but relies on a new SQL_CONVERTERS dictionary of the db helper. This will allow later inclusion of new base types.

from os.path import join
assert __file__.endswith(join('scripts', 'script2.py')), __file__
assert '__main__' == __name__, __name__
assert ['-v'] == __args__, __args__