code: function ( qu, value ) {
  		var operands, result;
  
  		result = false;
  		if ( sys.isArray( value ) ) {
  			operands = sys.flatten( qu.operands );
  			result = sys.intersection( operands, value ).length === operands.length;
  		}
  		return result;
  	}
docs: `$all` checks to see if all of the members of the query are included in an array
  `{array: {$all: [val1, val2, val3]}}`
  @name $all
  @memberOf module:documents/probe.queryOperators
  @example
  var probe = require("documents/probe");
  probe.find( data, {"categories" : {$all : ["cat4", "cat2", "cat1"]}} );