/*
 *  call-seq:
 *     dvector.ceil!   ->  dvector
 *  
 *  Replace each entry x of _dvector_ with the smallest integer not less than x.
 *     
 *     a = Dvector[ 1.1, -2.2, 5.3 ]
 *     a.ceil!   -> Dvector[ 2, -2, 6 ]
 *     a         -> Dvector[ 2, -2, 6 ]
 */ 
VALUE dvector_ceil_bang(VALUE ary) {