MozJPEG chroma subsampling and quality (#235)

* Adding chroma subsampling for mozjpeg

* Adding separate chroma quality.

* Preact sometimes removes the inline styles, this fixes it.

* Simplifying chroma subsample

* Adding comments

src/custom-els/RangeInput/index.ts

@@ -57,6 +57,8 @@ class RangeInputElement extends HTMLElement {
 
     this.insertBefore(this._input, this.firstChild);
     this._valueDisplay = this.querySelector('.' + style.valueDisplay) as HTMLDivElement;
+    // Set inline styles (this is useful when used with frameworks which might clear inline styles)
+    this._update();
   }
 
   get labelPrecision(): string {