Merge branch 'base64-sample-input' into 'master'

loadSample method that works with base64 strings

### Base64 baby!

This PR modifies the loadSample method so that when the input path is a base64 encoded audio file, MaxiLib will open it. It's obviously dependent on browser audio format support. Tested with the wav samples already included in the repo.

Also adds an example (with the base64 string blatantly pasted into the JavaScript code) called `23_SamplePlayer_base64.html`.

See merge request !1