Adding NFT examples with WASM and a Worker.

[kalwalt]

This is the continues of PR #7.
Add at least one example with WASM and a Worker. It should improve fps of 10/15%.

[kalwalt]

• First: I'm not sure if it make sense the video_threejs_wasm_worker.html example, i think i will delete it because it' is not necessary, it don't works properly and i don't want to spend my time resolving this.

• Second: these examples use another type of worker (nft/wasm_worker.js) inside a nft folder I'm thinking to find a solution to integrate the two versions.

[kalwalt]

Question: the flag ' -s BINARYEN_TRAP_MODE=clamp' should be added to all the libs or only for the WASM version?

[kalwalt]

With the last commit d10de2e i don't include the video + wasm + worker example.
@nicolocarpignoli The artoolkit.wasm_worker.js is inside the wasm_worker folder because i can not configure a right path for:

jsartoolkit5/examples/nft_improved_worker/wasm_worker/artoolkit.wasm_worker.js

Line 1 in d10de2e

var artoolkit_wasm_url = 'artoolkit_wasm.wasm';

if i set the path to point to the wasm lib inside the build folder it fails to load.

[kalwalt]

I added the flag -s BINARYEN_TRAP_MODE=clamp only to the WASM lib with this commit 1bb7a0f, though the other libs are the same. This means that probably this flag is ignored for the compilation of the .min and .debug libs (compiled with asm)