fixed mising expectation on test
+2 failing tests: should output a function for start and end event
+2 test pass: output a function for start and end event of the note
+1 failing test: function on start should call instrument note
+1 test pass: function on start calling instrument note
+1 failing test: calling with notenum 0 on start
+1 test pass: calling with notenum 0 on start
+1 failing test: should call play on note returned by instrument
refactor fake instrument to respond to note(...).play calls
+1 test pass: call play on note returned by instrument on start event
+1 failing test: should call stop on note on end function
+1 test pass: calling stop on playing object returned from instrument.note(...).play