implement simple,trivial test cases (Literals and PMFs)

...icationlevel/functions/util/tests/MeanCalculatorTest.java

...l.mm.applicationlevel/testfiles/boolean-literal.functions

...s.dml.mm.applicationlevel/testfiles/boolean-pmf.functions

...ml.mm.applicationlevel/testfiles/double-literal.functions

...es.dml.mm.applicationlevel/testfiles/double-pmf.functions

...rtes.dml.mm.applicationlevel/testfiles/enum-pmf.functions

...s.dml.mm.applicationlevel/testfiles/int-literal.functions

...artes.dml.mm.applicationlevel/testfiles/int-pmf.functions