Calculate the length of time required to afford a house down payment.
There are two ways to use this program: graphically and on the command line.
While in the source directory, type the following into your terminal (using python if on Windows and python3 if on GNU/Linux):
$ python main.py
...will run the graphical version of the program.
$ python main.py cli
...will run the command line version of the program.
The calculation uses the formula for annual interest compounded monthly, or P(1 + R / 12).
