JS implementation added

[l-ra]

Based on your Java code I created the javascript implementation. It is located in JS folder and consists of three files:

• proquint.js - the implementation itself
• proquint.html - demo page using the JS code to convert hex <-> quints
• script.js - auxiliary script driving the html gui
  The demo page is available online as a github page in my forked repo.
  The JS implementation/demo can be used to quickly demonstrate how your algorithm works from a web browser without need to compile code.