Adding MIDI.js

Adding midi.js which is used  to create a MIDI-app on the web.

This was found at https://github.com/mudcube/MIDI.js and it has an MIT
license. Current version is 0.3.0
Tweaked the package.json

Name needed to be corrected to reflect the directory.
Merge pull request #3279 from JGallardo/master

Adding MIDI.js