all
- clean up the API for the first release
- allow to use any INI config file, use defaults if not specified
  perhaps also extract getConfig() to RPMMD::impl::Config
- clean up logging & output
  - logs must not be localized
  - we must be able to turn output to stdout/stderr off
  - send localized messages only via callback (instead of printing directly)?
  - actually enable localization

tests
- enable testing on DB
- enable testing with remote (self-served?) repos

