Add HTML color picker, update p5.js

[ozgunozankilic]

Hi. I really liked your creation as an old Processing enthusiast and wanted to contribute.

• The old color pickers are replaced with HTML color inputs. They still look the same from the outside, at least in Chrome, Firefox, Opera, Brave, and Tor Browser. It should work with Safari as well, but I could not test it.
  
  Some styling changes were made accordingly and outlines are used instead of borders to achieve the same look. Cross-browser styling compatibility for the color input is a bit confusing, so the CSS additions might not be perfect. Color randomization still works on the old palette. Making the randomization a bit smarter may help with obtaining a more harmonious color scheme, but having those crazy and sometimes clashing colors might be intentional, so I did not change it. Perhaps a color shuffling button can be added?
• Bottom padding is tweaked to improve the vertical alignment inside .brush and .setting. Here are the old and the new versions:
  
• p5.js is updated to v1.4.0 and everything seems fine.