Improve news plugin
Improve nicebot plugin
Improve oeis plugin
Fix help plugin to cope with non-existent plugins
Improve help for pastebin plugin.

Also create a default on_help implementation which returns the names.
Improve remind plugin help
Improve help for seen plugin
Improve sendto help
Improve help on sentiments plugin
Improve sprunge help
Improve steam help
Improve tee plugin help
Improve trains plugin help