Content fixes

[bonartm]

This is a cleaned up version of #5. I rebased my changes on top of the most recent changes in master and changed my commits' history and names for better traceability. I deleted three unused/unmaintained articles but I can revert that if wished.

• put the application code in a mobydick folder
• used python -m pytest instead of pytest to test modules in another folder
• append mobdydick. to import statements
• removed articles that are not up to date anymore
• fixed file pates and code blocks in markdown files