bot now can save/load resource from file

we are preparing for a simple scoring system (nutshells)
to make life fun.
Fix a typo
bot: resource is merged from configuration
bot/core: bot_score! returns the last score
lib.core: fix typo
lib.core: fix typo
Add nutshell system to some plugins (see long notes)

* xy: when a user play games they may earn new nutshells,
      a warning will be sent if they play too much (300 seconds)
* sensors: badwords = -1 nutshells
* give: you can give someone some nutshells
* core lib.: can be reloaded (actually there is no way to reload it though)
* configuration can be saved, loaded from files
bot.p.bot: clean up
bot.p.give: can give someone some nutshells (fixed)
bot new plugin nutshell
clean up
bot.xy: fix a bug when caching. thanks miyo
bot.give: give shell only accepts positive shell
bot.bot: cache for "save" is now 1 minutes
bot.give: user shouldnot give too many nutshells
bot.give: fix message destination
bot.give: shouln't give shells to someone-self
bot.xy: fix typo
bot.give: ensure to give shell to online user