Updated .gitignore to exclude JES backup/log files

After merging this pull request, you can delete the `*.pybak` and `*.pylog` files from your repository. They're not necessary for the operation of the program, and the `.pylog` file can leak sensitive information about your personal machine.

I think you'll need to use the git console to remove the file. The command for that is:

    git rm <filename>

when you're inside the repository folder on your own machine. After your next commit/sync, those files will be deleted from the repo.