Implementation of the getSamples function

[ThatcherC]

The getSamples() function was left empty in the origin branch. I used wav.js for a project of mine and implemented the function. The samples from the .wav are loaded into the array this.dataSamples when this.getSamples() is called.

[pneyrinck]

Thank you for getting this going! However, I think it will fail/crash for large WAV files because the file reader loads the entire file into the array buffer.