Fix React errors and warnings

[vanfossen]

Currently not entirely sure of the exact problems. Some warning are of unused variables. At one point there were warnings from depreciated function calls.

[vanfossen]

Fixed multiple warnings in the program. Most were caused by unused statements.

The following warnings still exist. Currently unsure how to fin:

WARNING in [eslint] 
src/components/Spectrum.jsx
  Line 8:7:   'd' is assigned a value but never used                                                                                                                                                                                                                                              no-unused-vars
  Line 22:9:  Assignments to the 'd' variable from inside React Hook useEffect will be lost after each render. To preserve the value over time, store it in a useRef Hook and keep the mutable value in the '.current' property. Otherwise, you can move this variable directly inside useEffect  react-hooks/exhaustive-deps

[vanfossen]

Fixed the last two existing warnings