Making these changes, the code becomes more robust and easier for
adding the new features.
-Introduce the LocationStats class representing the statistics
-Add the pretty_print() method in the LocationStats class
-Add additional '-' for the program options
-Add the verify_program_inputs() function
-Add the parse_locstats() function
-Rename 'results' => 'opts'
-Add more comments
Differential Revision: https://reviews.llvm.org/D71868