Teach CTest to parse output for <CTestMeasurement> in addition to
<DartMeasurement> for measurements defined at runtime.
Use a new class (cmCTestTestMeasurementXMLParser) derived from cmXMLParser
to parse the data and attributes these XML elements. This is an improvement
over our previous approach of using a series of regular expressions.
As part of this commit we also rename some member variables and methods
to make their purpose more clear.
DartStuff -> AllTestMeasurementsRegex
DartStuff1 -> SingleTestMeasurementRegex
DartString -> TestMeasurementsOutput
GenerateDartOutput() -> GenerateCTestXML()
GenerateRegressionImages() -> RecordCustomTestMeasurements()
cmCTestRunTest::DartProcessing() -> ParseOutputForMeasurements()
