Some major changes in file i/o

The code is almost working! :smile: But still changes are needed.
Applied AutoPep8 to crypto.py . It seems that the xor vignere is breaks
on lowercase 'k'
Highlighted Warning
Rewrote Vigenere

Uses numbers to store text now. The code is working Now.
Formatting changes in CLI frontend
Closing Mechanism
More changes to frontend and new default file
:smile: Full program is working.

Also added how to use.txt
UI changes