Feature Request: add the option to ignore specific users

[keylime-unicorn]

So I have my bot account send example commands to my twitch chat for viewers to see usage of the various commands. The issue I run into is that the example commands are being registered as commands from my bot account user. It would be nice to set a list of ignored usernames (more than likely to be used for bot accounts) and have any potential command messages sent by these users be ignored by the task list.

[keylime-unicorn]

If this sounds like something you would be interested in adding, I would be willing to take a crack at a PR if you are open to it!