Added helper functions for channel and user lists to make the API a bit ...

...more friendly

Added support for the following methods: chat.delete, chat.update, channel.history, channel.list, users.list, auth.text, channels.info, channels.invite, channels.join, channels.leave, channels.mark, channels.setPurpose, channels.setTopic, emoji.list, stars.list

I hope you'll forgive a slight reordering of some of your original code
Why not use full variable names? I know `channel_list` is taken (function above), but `channel_list_` or something might work - I'm just not a fan of abbreviated variable names. Perhaps also use `channel` instead of `c` just below.