Use the `CustomEvent` constructor instead of `document.createEvent`.
Make number of channels configurable.
fix from vizv, https://github.com/mattdiamond/Recorderjs/commit/1e43dca0a3d754ccea8f1c3f3907fb6ceced3031
adding in changes from KenPower patch to forceDownload
add ability to make mono-audio, from agrueneberg