Reformatted timestamps on log entries and force focus on log text window.

[Jeff-Moorhead]

I have implemented two improvements in this pull request. First, I added cleaner formatting for the timestamps in the user log. Dates now appear like "July 6, 2018 at 8:29AM" instead of the hard to read raw datetime object. This will allow users to more easily navigate their log. Secondly, I added one line of code that forces the cursor to move to the log window when the user wants to create an entry, so that the user doesn't have to click into the window. This improvement will allow for a more seamless user experience.

I moved a lot of stuff around and refactored a lot of the classes and functions in the project. I restructured the project into a more pythonic package structure, with a main.py file so the project can be run using "python -m prog-o-meter". Lastly, I implemented a means of user data storage that is much cleaner by using json in one single users.json file, rather than creating individual text files for each user. This way, the program will store users.json in the project directory, rather than the current directory.

Please let me know if there is anything in my code that does not comply with the project contribution guidelines!

If this is your first pull request to the prog-o-meter project, we would really appreciate it if you would fill out this Google form.
This lets us know more about our contributors, and what we can do to make it easier and nicer to contribute to the prog-o-meter project.
Please submit your answer here and put an 'x' in the box below.

• [x ] It is my first pull request to prog-o-meter, and I have answered the survey
• This is not my first contribution to the prog-o-meter