check state duration and some fixes around previous_state, may fix #258
minor tweaks missed in last commit
move state duration calc from email.rb to processor.rb
Merge pull request #290 from ali-graham/258_email_tweaks

duration in emails, various processor & filter tweaks
refactor delays filter, remove mass client failures filter
clean up
Merge pull request #293 from jessereynolds/filter_refactor

refactor delays filter, remove mass client failures filter
fix behaviour when unauthorised, don't send disconnect on error as it's against XMPP spec
Merge branch 'master' of github.com:flpjck/flapjack into threading_restructure