Unwanted characteristicvaluechanged event

https://github.com/stevennyman/webbt/blob/c8e15a3a3c2c884735cdee2a5a52a3f7838dde79/extension/polyfill.js#L152

This appears to be dispatching the "characteristicvaluechanged" event every time the characteristic is read, regardless of if it has changed or not. That's messing up my application logic, which is working on Chromium browsers.