- Minor other stuff

Resolve "Accept None parameter for concatenate"

Closes #7

See merge request !4

- Added new data cut with custom user function support (not ideal atm)

- Add configs for regression dataset

- Added command line tools to setup.py

- Remove all optional arguments in the parser. Now, a config file is always needed! Updated docs due to this.
- Added default_config.toml file
- Implemented automatic generation of API docs
- Fix __version__.py
- Added flush_freq argument in the HDF5Sink.
- Minor other fixes.