Unicode engine with repr(engine)

[elbenfreund]

There seems to be an issue when calling repr(engine) on an sqlalchemy engine instance like we do here
If the engine is an sqlite one and the path contains unicode we end up with an UnicodeError.

[tests/conftest.py:76: in runner
    return CliRunner().invoke(hamster_cli.run, args, catch_exceptions=False, **kwargs)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/click/testing.py:279: in invoke
    prog_name=self.get_default_prog_name(cli), **extra)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/click/core.py:696: in main
    rv = self.invoke(ctx)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/click/core.py:1057: in invoke
    Command.invoke(self, ctx)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/click/core.py:889: in invoke
    return ctx.invoke(self.callback, **ctx.params)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/click/core.py:534: in invoke
    return callback(*args, **kwargs)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/click/decorators.py:57: in new_func
    obj = ctx.ensure_object(object_type)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/click/core.py:456: in ensure_object
    self.obj = rv = object_type()
hamster_cli/hamster_cli.py:119: in __init__
    super(Controler, self).__init__(lib_config)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/hamsterlib/lib.py:67: in __init__
    self.store = self._get_store()
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/hamsterlib/lib.py:88: in _get_store
    return cls(self.config)
../../.virtualenvs/hamster_cli_py27/lib/python2.7/site-packages/hamsterlib/backends/sqlalchemy/storage.py:84: in __init__
    self.logger.debug(_("Engine '{}' created.".format(engine)))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <[UnicodeEncodeError("'ascii' codec can't encode characters in position 67-76: ordinal not in range(128)") raised in repr()] SafeRepr object at 0x7fdb0399b248>

    def __repr__(self):
>       return 'Engine(%r)' % self.url
E       UnicodeEncodeError: 'ascii' codec can't encode characters in position 67-76: ordinal not in range(128)
](url)