Issue #27 : new add (#51)

* Issue #27: change return code in Dotify to exception (also in Main)
	modified:   src/main/scala/modbat/mbt/Dotify.scala
	modified:   src/main/scala/modbat/mbt/Main.scala

* Line 45, I replaced return 1 by throw e in Main.scala

* in file MBT.scala, severals System.exit(1) replaced by throw(error)

* in file MBT.scala, System.exit changed by throw

* Issue #27: change exit to exception.
	new file:   src/main/java/modbat/mbt/NoTransitionException.java
	modified:   src/main/scala/modbat/mbt/MBT.scala

* Remove return 1 replaced by throw exception.