setUpEnvOnPlay = function(that, arg){ //_
	if ( arg && arg.env ) {
		that.env.attack  = lodash__WEBPACK_IMPORTED_MODULE_3___default.a.get(arg, 'env.attack', that.defaultEnv.attack);
		that.env.decay   = lodash__WEBPACK_IMPORTED_MODULE_3___default.a.get(arg, 'env.decay', that.defaultEnv.decay);
		that.env.sustain = lodash__WEBPACK_IMPORTED_MODULE_3___default.a.get(arg,'env.sustain', that.defaultEnv.sustain);
		that.env.hold    = lodash__WEBPACK_IMPORTED_MODULE_3___default.a.get(arg, 'env.hold', that.defaultEnv.hold);
		that.env.release = lodash__WEBPACK_IMPORTED_MODULE_3___default.a.get(arg, 'env.release', that.defaultEnv.release);
	}
	else {
		that.env = {
			attack  : that.defaultEnv.attack,
			decay   : that.defaultEnv.decay,
			sustain : that.defaultEnv.sustain,
			hold    : that.defaultEnv.hold,
			release : that.defaultEnv.release
		};
	}

}
Set the ADSR volume envelope according to play() arguments, or revert to defaults *