Changes between 6.6.3 and 6.6.4

Module changes

• Replaced help pastebin with clbin.com
  • ptpb.pw shut down due to abuse — see ptpb/pb#246 for more
  • More news on this front (reducing Sopel's dependence on specific pastebins)
    in a future release. Several ideas are under consideration.
• Cleaned up code in instagram and unicode modules
• Core modules now use bot.channels instead of deprecated bot.privileges

Core changes

• Privilege tracking now always updates both bot.channels & bot.privileges,
  where before some handlers only updated one or the other
  • This should have zero effect on behavior, but do report any observed.