Pizzicato Versions Save

• Removes possibility of adding invalid effects to sounds.
• Adds support for AMD and CommonJS modules.

• Adds dub delay (PR #12 by @JohnPaulHarold)
• Adds ring modulator (PR #13 by @JohnPaulHarold)
• Adds possibility of cloning Sound objects.

• Adds panner effect (PR #3 by @kristianj)
• Adds convolver effect (PR #4 by @JohnPaulHarold)
• Adds reverb effect (PR #5 by @JohnPaulHarold)
• Adds ping-pong delay effect (PR #6 by @JohnPaulHarold)
• Adds parameters when and offset in Sound objects

This release allows the addition and removal of effects without interrupting an ongoing sound.

This issue contains bug fixes for two issues:

• #1 Effects now are removed from the audio graph when using removeEffect.
• If not looped, sounds from a file go back to a "stopped" state after finishing.

• Adds attack to Pizzicato Sounds.
• Sets default sustain and attack to avoid the clicking sound when starting and stopping sounds.
• Adds possibility to get an analyser node for a Pizzicato Sound:

var sound = new Pizzicato.Sound();
var analyser = sound.getAnalyser();

• Adds a global volume property that affects all Pizzicato sounds: Pizzicato.volume
• When there is an error initializing a sound from a file, the callback is called with an error object as parameter.
• Adds a fallback mechanism when loading sounds from a file by passing an array of fallback file paths:

var bird = new Pizzicato.Sound({ 
    source: 'file',
    options: { path: ['base/tests/non-existent.wav', 'base/tests/bird.wav'] }
};

Allows creating sounds from multiple sources and adding effects.