The help plugin should allow reading from a docstring

[shaunduncan]

Sometimes a usage string used by the help plugin can get quite long for some plugins. Consider allowing a plugin's docstring as a fallback. Some thought should be considered so that the length of this sent over chat is limited (for IRC rate limiting)

[shaunduncan]

In addition to this, there probably shouldn't really be a help plugin. Commands should natively support 'help' as an argument, they already support help strings.