Litecrypt

Usual Code refactoring

Removed typo for Python 3.6 support -> fixed user warning upon usage with versions less than 3.7

Default usage for compute-intensive key derivation functions has been deprecated and is now provided as an option.
Fast encryption is now the default

Fixed engines for MySQL & PostgreSQL

Restructured directory hierarchy for modularity and separation of concern

Minor bug fix for GUI: Resolved layout mismatch issue on Windows platform.

v.0.04
Major Code Refactoring & Optimization.