Use raise to reraise exceptions.

Use 'raise' instead of 'raise <exception_name>' to reraise exceptions.
Run Sleuth as module.

Sleuth can be run as `python -m sleuth <pyfile>`. Commandline arguments
are supported and the specified Python file is run with exec().
Execute config file and script.

Sleuth processes the config file and executes the main script.
Currently, Sleuth decorators only work for functions defined in modules
outside of the main script.
Cleanup.