Use command name method instead of hardcoded string.

I want to read documentation on a second display (in terminal, tail -f /path/to/file), instead of displaying it in a tiny ST panel.
At first I thought it's better to modify existing Anaconda command, but decided to subclass into a separate command.
I still would like to see a small change in the original code, so that prepare_data calls my subclass, when documentation is found.