Refreshed command line interface

Restructured the CLI with major changes.

1. Dropped ability to specify tree algorithm options such as determinization, impurity measure, splitting predicate from the command line.
2. Added ability to read from a config file.
3. Now prints the configurations before running the benchmark.
4. Added ability to clean the default output folder (decision_trees) as well as default results files (benchmark.*).

Additional info: There will be a default 'system' config file as well as any number of user config files. The help message shows how a sample user config file can be generated. The documentation must add details on the options that can be set via the config files.