FIX: leaking of Uploaders in T_FileProcessing
remove useless iostream include from T_BlockingCounter
TEST: unit test for massive concurrent access to SynchronizingCounter
FIX: race condition on Reader destruction
adapt IoDispatcher to new Reader API
adapt T_AsyncReader test to new API
Merge pull request #340 from reneme/fix_reader_dtor_race

FIX: Race Condition in Asynchronous Reader Class

This applies the same thread start/stop pattern to the Reader template, that I already used recently for the AbstractUploader base class. The situation here is a bit different, but I suspect it to potentially cause problems (data race, premature memory releasing). I am not a 100% sure, that this fixes the seen deadlock/crash behaviour, but it is a potential bug.

Additionally this contains a new unit test for the SynchronizingCounter template that was the suspect before, but turned out to work fine for now.