Refactor blame analysis code.
- Change class BlameTree to BlameAnalysis.
- Change class BlameTreeAnalysis to BlameTree.
- Change variable dynamicCounter in BlameAnalysis to dpc.
- Change data structure of variable trace in BlameAnalysis to
  vector<vector<BlameTreeShadowObject>>.
Merge branch 'blame-analysis' of https://github.com/corvette-berkeley/shadow-execution into blame-analysis