Zoom level fix + transpiled source code

Hello, I've changed the default import to be the umd import as I think that will be easier for a lot of people using the library. If you would like to import and customise parts of the library, please import individual files from the lib/ folder.

https://unpkg.com/browse/waveform-playlist@4.2.4/

• Zoom out issue fixed when devicePixelRatio was < 1.