Changed the validator to check if items exist before storing the value. If one of the items doesn't exist, the program will terminate and it will let the user know that there the yaml file has to be fixed.

*Currently I have fixed the run_tests.py checks to check if the user's directories exist on their system and it prompts them to make the directories. I'm currently working on checking if the extension_perf_reports dir exists and if the content of the extension_perf_testing directory and base_profile directory exists.

*There are many several levels in the directory and here . Here is the basic outline of the directory structure:

*I haven't went through a thorough discussion with Alice about which files should be validated in the base_profile dir. From what I 've gathered from the other discussions we had, the perf.js file will crash the program is it's non-existantexistent.

*Currently I have fixed the program checks to check for the existence of the base_profile dir and it also checks if the bookmarkbackups, Cache dirs and perf.js dir exist.