Fix for issue #36. Task.spawn(Spawnable) added.

Can start a task without explicitly creating a task object. Supply a lambda expression or an instance of a Spawnable object like this:

Task.spawn( () -> {
     do pausable stuff.
});

Another minor fix was a data race (discovered during testing TestLambda) that synchronizes Task.informOnExit

	new file:   src/kilim/Spawnable.java
	modified:   src/kilim/Task.java
	modified:   src/kilim/analysis/ClassFlow.java
	modified:   src/kilim/analysis/ClassWeaver.java
	modified:   src/kilim/analysis/MethodFlow.java
	modified:   src/kilim/analysis/MethodWeaver.java
	modified:   test/kilim/test/TestLambda.java