runner: implemented Sink classes
runner: style
runner: finalized sink classes
fixed handling of fread error in helper
fixed test compilation
AsyncFdOutputSink: handling of data transmission in the hands of the provider and fixed handling of program termination via a signalfd
Reverted changes to the Epoller api, since the required functionality was implemented via the Sink system
runner: put writing code back in the hands of the OutputSink
restored disabled tests
release futex on "running_" only when everything has been set back to a proper state
runner: ensure all sinks are properly cleaned up upon termination
runner: added cleanup test