Separated Py into general GUI and VM's interface

This way the VM can be used as a command line executable, which starts
its own interface for requesting and printing data.
The GUI (“solGUI.py”) works just as a tool for the user to manage both
the compiler and the vm in an easier way.
Folder reorganisation

The folder “tests” is now inside the root, that’s because the tests are
used both for the compiler and the virtual machine. This makes the
“source” folder inside the “compiler” folder useless, hence it has been
removed and its files now are simply inside “compiler”.
I’m not sure whether or not the folder “Game of Life” (which has been
stripped of the underscores) should stay inside the root or the “tests”
folder.