Finalized the program:

 1. Uses nano for messages.
 2. Indents logs against the timestamps.
 3. Formatting (newlines at the ends of logs) is now consistent and not dependent on input (always two newlines at the end of a log).
 4. Dump now uses print_file as it should have before.
 5. It is not possible to enter a empty message (either by closing nano without any edits or inputing only whitespace).
 6. General bugfixes and code comments.