file: embed polyfill for blob and file

[jimmywarting]

This is a kind of better blob implementation cuz it can references other blobs and dose not have to hold all data in memory.
it's a way better implementation for later being able to create blob's that are backed up by the disk.

it mostly comes from fetch-blob with some minor adjustments

[saghul]

Thank you! Can you regenerate the C file please?

[jimmywarting]

Plz Tell me how. This is my first contribution.

[saghul]

Ssure, just run make js

[jimmywarting]

Thx, Done!

[saghul]

Looks like a test is failing, can you check?

[jimmywarting]

A blob where constructed with invalid arguments in test-ws-send.js:13

- new Blob(arrayBuffer)
+ new Blob([ arrayBuffer ])

[saghul]

Thanks a lot!

[saghul]

I was thinking about using your FormData libary to polyfill FormData, what do you think?

[jimmywarting]

Sure. Feel free to copy as much or as little as you want