Ucum normalized

[bryantaustin13]

This branch was built from #96. That one needs to be merged first.

Running the below test fails because the engine returns { "value": 0.0002, "unit": "m2" } which is true and matches the expected output, but not in a normalized way. This fix normalizes so the test passes.

<?xml version="1.0" encoding="utf-8"?>
<tests xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://hl7.org/fhirpath/tests" xsi:schemaLocation="http://hl7.org/fhirpath/tests ../../testSchema/testSchema.xsd"
	   name="CqlArithmeticFunctionsTest">
	<group name="SingleTest" version="1.0">
		<test name="Multiply1CMBy2CM" version="1.0">
			<capability code="ucum-unit-conversion-support" />
			<expression>1.0 'cm' * 2.0 'cm'</expression>
			<output>2.0'cm2'</output>
			<!-- TODO: make the units multiply -->
		</test>
	</group>
</tests>