JSLint fixes for separation of Frontend & Backend NDT

[shredtechular]

This PR's main focus are fixes to the js to ensure a clean JSLint on the HTML5-frontend/script.js and HTML5-frontend/ndt-library.js files.

The JSLint fixes entailed:

• a lot of spacing changes in statements,
• a lot of moving around of methods
• some minor logic changes as well

---

This change is