Fixed error handling

Return != 0, when command fails. Also exit immediatly, when database cannot be fetched.

Support database arguments via config

Merge pull request #5 from kuborgh/stmllr-db-arguments

Support additional arguments for DB import/export

Support for large databases

Database can now be sent as file to prevent out-of-memory issues while streaming.

First stable release

Merge pull request #3 from kuborgh/FEAT-symfonydatabase

allow default symfony database configuration