BLOB max increase to 1GB

Currently, the BLOB cannot be more than 200 MB https://github.com/feross/render-media/blob/a445b2ab90fcd4a248552d32027b2bc6a02600c8/index.js#L76 . As stated in https://github.com/feross/render-media/issues/18 there is a sanity cap of 200 MB. Browsers now allow much larger BLOBs around 900 MB with no issue.

Since using a larger BLOB does not cause any errors or warnings, and the only reason for the 200 MB limit is because of a bothered UX from waiting, I recommend the max size increase to 1 GB.

This issue arose while using Webtorrent to fetch a 500 MB .webm file. However, it _does_ work on instant.io so maybe there's a difference in code there.