code: function Data( data ) {
  
  	// INSTANCE ATTRIBUTES //
  
  	this._config = {};
  	this._data = data;
  
  	// ACCESSORS //
  
  	// Opinionated defaults...
  	this._accessors = {
  		x: function( d ) {
  			return d[ 0 ];
  		},
  		y: function( d ) {
  			return d[ 1 ];
  		},
  		z: function( d ) {
  			return d[ 2 ];
  		}
  	};
  
  	return this;
  }
docs: DATA // 
  FUNCTION: Data( data )
  Data constructor. Creates a new data instance.
  
  @constructor
  @param {array} data - input data is expected to be an array of arrays; e.g., [[[0,0],[1,1],...,[N,N]]] or [[{x:0,y:0},{x:1,y:1},...{x:N,y:N}]]. Elements in the outer array are treated as separate datasets.
  @returns {object} data instance