Cleanup ContourTreeAugmented

This PR is to fix #417 (closed) . This PR does not add new functionality but primarily cleans up issues to improve compliance with VTKm guidelines (e.g., syntax style). The main changes in this PR are:

• Add support for VTKm logging
• Replace std::cout prints in ContourTreeApp with VTKm logging
• Replace collection of timings in the ContourTreeApp, filter, and the worklet with VTKm logging
• Remove use of DEBUG_TIMINGS define previously used in the ContourTreeApp
• Replace use of the PPP2 acronym in class/variable names to comply with VTK-m coding style
• Capitalize and rename class methods and member variables throughout the ContourTreeAugmented code base to comply with VTKm coding style
• Fix memory leak in distributed parallel contour tree (e.g. ContourTreeUniformAugmented.hxx:497)
• Add Doxygen-style documentation for the ContourTreeAugmented filter and update documentation of the worklet
• Update unit test for the ContourTreeAugmented filter to run test with varying augmentation settings
• Add detailed unit test for the ContourTreeAugmented worklet to test the main steps of the contour tree computation rather than just the end result
• Move EulerTour code to the approbriate contourtree_augmented/postprocess subfolder
• Place ContourTreeBlockData in an appropriate namespace