function isCastingMode( v ) {
	var i;
	for ( i = 0; i < len; i++ ) {
		if ( v === MODES[ i ] ) {
			return true;
		}
	}
	return false;
}
Tests whether an input value is a supported ndarray casting mode.

@param {*} v - value to test
@returns {boolean} boolean indicating whether an input value is a supported ndarray casting mode

@example
var bool = isCastingMode( 'none' );
// returns true

bool = isCastingMode( 'equiv' );
// returns true

bool = isCastingMode( 'safe' );
// returns true

bool = isCastingMode( 'mostly-safe' );
// returns true

bool = isCastingMode( 'same-kind' );
// returns true

bool = isCastingMode( 'unsafe' );
// returns true

bool = isCastingMode( 'foo' );
// returns false