Introduce the testing library Midje
Better tests in `majic.core`

This tests whether the `-main` function can handle both no input and intended input (like "1234".)
Test for documentation

This introduces a test for the existence of docstrings.
Test the utility functions

This introduces a few simple tests for the functions in the `majic.util` namespace.
Merge pull request #11 from emiln/feature/2-introduce-testing

Feature: issue #2 - introduce testing