Nodejs buffers in Summon apps

[brghena]

It would be a good idea to unify the javascript used in Summon apps with the nodejs we use to interact with BLE devices on desktop. The bluetooth.js script goes a long way towards providing that.

An additional bit that would help is if we could use nodejs-style buffers rather than Uint8Array types. https://github.com/feross/buffer supports nodejs-style buffers in the browser and seems like it would be a good choice to be included in Summon.