message: adding some doc image
diff: @@ -13,13 +13,21 @@ interface FMOscillatorOptions extends ToneOscillatorOptions {
  }
  /**
  - * @class FMOscillator
  - *
  - * @extends {Tone.Source}
  - * @constructor
  - * @param {Frequency} frequency The starting frequency of the oscillator.
  - * @param {String} type The type of the carrier oscillator.
  - * @param {String} modulationType The type of the modulator oscillator.
  + * FMOscillator implements a frequency modulation synthesis
  + * <pre>
  + * +-------------+
  + * +---------------+ +-------------+ | Carrier Osc |
  + * | Modulator Osc +>-------> GainNode | | +--->Output
  + * +---------------+ | +>----> frequency |
  + * +--> gain | +-------------+
  + * | +-------------+
  + * +-----------------+ |
  + * | modulationIndex +>--+
  + * +-----------------+
  + * </pre>
  + * @param frequency The starting frequency of the oscillator.
  + * @param type The type of the carrier oscillator.
  + * @param modulationType The type of the modulator oscillator.
  * @example
  * //a sine oscillator frequency-modulated by a square wave
  * var fmOsc = new FMOscillator("Ab3", "sine", "square").toMaster().start();
  