bot. clean up
bot.give: fix bot variable name in plugin class
bot.cron: add. simple cron job support
bot.give: add username in a error message
bot.bot: reload multiple plugins
bot.bot: reduce some error message
bot.nutshell: find max, add aliases

now we can use !ns instead of !nutshell
bot.give: update help message
bot.cron: fix plugin date
bot.core: add fake plugin to reload core library
bot.nutshell: fix message
bot: nutshell masterbank add

* valid user is off the form Symbol or online user
* masterbank now collects all bad nutshells or give it away
* mastebank will accepts negative nutshells to deal with xy game
* can not query nutshell of random user
Accept only 1 virtual user = :masterbank
bot: update doc
Update license => GPL2