Two workers & worker termination (#198)

* Refactoring codecs

* Plugging in new processor

* Fixing decorator

* MozJPEG free issue

* Better worker aborting, and terminate workers that aren't used for 10 seconds

* Better comment

* Ooops, half-typed comment

* Uncommenting problematic line

* Surma fixed it!

* Abstracting WASM initialisation

* Better comment

* Don't need this.

* Adding ticket

* noInitalRun

* Reverting MozJPEG issue demo

* Making a const for worker timeout

* Inline docs

* Bail early rather than nesting

* Addressing nits

src/codecs/mozjpeg/encoder-meta.ts

@@ -0,0 +1,41 @@
+export enum MozJpegColorSpace {
+  GRAYSCALE = 1,
+  RGB,
+  YCbCr,
+}
+
+export interface EncodeOptions {
+  quality: number;
+  baseline: boolean;
+  arithmetic: boolean;
+  progressive: boolean;
+  optimize_coding: boolean;
+  smoothing: number;
+  color_space: MozJpegColorSpace;
+  quant_table: number;
+  trellis_multipass: boolean;
+  trellis_opt_zero: boolean;
+  trellis_opt_table: boolean;
+  trellis_loops: number;
+}
+
+export interface EncoderState { type: typeof type; options: EncodeOptions; }
+
+export const type = 'mozjpeg';
+export const label = 'MozJPEG';
+export const mimeType = 'image/jpeg';
+export const extension = 'jpg';
+export const defaultOptions: EncodeOptions = {
+  quality: 75,
+  baseline: false,
+  arithmetic: false,
+  progressive: true,
+  optimize_coding: true,
+  smoothing: 0,
+  color_space: MozJpegColorSpace.YCbCr,
+  quant_table: 3,
+  trellis_multipass: false,
+  trellis_opt_zero: false,
+  trellis_opt_table: false,
+  trellis_loops: 1,
+};