Added options via #define directives in the experiments vs NAMOA*
main.cpp. Also updated README.txt etc files.

- We can now choose the number of objectives in
  experiments/vs_namoa_star/ by changing the OPTION_NUM_OBJECTIVES
  #define in the experiment's main.cpp file.
- Updated the main README.txt file plus the experiments/vs_namoa_star
  README.txt file plus the
  experiments/vs_namoa_star/data/graphs/GRAPH-INFO.txt file.
- Also changed other previously hardcoded defaults of the
  experiments/vs_namoa_star experiment to options #defined in the
  main.cpp file (e.g. OPTION_QUERIES_FILE_NAME).