Revert "added "throws exception" to signal method headers"

src/main/java/teetime/framework/AbstractStage.java

src/main/java/teetime/framework/pipe/InterThreadPipe.java

...in/java/teetime/framework/signal/OnStartingException.java

...java/teetime/framework/signal/OnTerminatingException.java

src/main/java/teetime/framework/signal/StartingSignal.java

...main/java/teetime/framework/signal/TerminatingSignal.java

src/main/java/teetime/stage/Cache.java

src/main/java/teetime/stage/CollectorSink.java

src/main/java/teetime/stage/ElementDelayMeasuringStage.java

...n/java/teetime/stage/ElementThroughputMeasuringStage.java

src/main/java/teetime/stage/Relay.java

src/main/java/teetime/stage/basic/Delay.java

...ain/java/teetime/stage/basic/distributor/Distributor.java

src/main/java/teetime/stage/basic/merger/Merger.java

src/main/java/teetime/stage/io/Printer.java

...n/java/teetime/stage/stringBuffer/StringBufferFilter.java

...rmancetest/java/teetime/examples/loopStage/Countdown.java