rewrite tests for notesequence context to use custom matcher, turned 3 test into 1
+1 test pass: calling funseq.start(...) with proper context paramter from noteseq
+560 failing tests: interlaced execution on funseq on two different contexts
fixed use of contexts on spec
+560 test pass: interlaced calls of noteseq functions with two different contexts
+1 failing test: noteseq should stop playing note when stopped
+1 test pass: noteseq should stop playing note when stopped
+280 failing tests: calling end event without start event should not throw
+280 test pass: calling end event without start event should not throw
+1 failing test: report time 0 from clock signal producer
+1 test pass: producing signal with time 0 from clock signal producer