Flowdock handler
added FlowdockFormatter
refactored FlowdockHandler, removed formatting, using the FlowdockFormatter instead
Merge pull request #337 from domnikl/flowdock-handler

added Flowdock handler
Wrap up flowdock handler, refs #337
Merge remote-tracking branch 'hver/master'
Rename MinMax handler to Filter handler, wrap it up, refs #338
Update changelog/readme/release target
CS fixes
Fixed documentation.