Collected exceptions

fixes #221
This branch introduces techniques which allow to log exceptions and collect them afterwards

See merge request !55

collectedExceptions

Conflicts:
	src/test/java/teetime/stage/InstanceOfFilterTest.java

moved declareActive to Stage

See merge request !58

Ascii javadoc

Added sketches which are more concisely than simple images.
Furthermore, this introduces new javadoc tags, such as: stage.output, stage.input and stage.sketch

See merge request !57

corrected link