function expandShape( ndims, shape, ndmin ) {
	var out;
	var i;

	out = [];
	for ( i = 0; i < ndmin-ndims; i++ ) {
		out.push( 1 );
	}
	for ( i = 0; i < ndims; i++ ) {
		out.push( shape[ i ] );
	}
	return out;
}
Prepends singleton dimensions in order to satisfy a minimum number of dimensions.

@private
@param {NonNegativeInteger} ndims - number of dimensions
@param {Array} shape - array dimensions
@param {NonNegativeInteger} ndmin - minimum number of dimensions
@returns {Array} output shape array