/*
 *  call-seq:
 *     dvector.concat(other)  -> dvector
 *
 *  Appends the elements in _other_ to dvector.  _other_  can either be a Dvector or a 1D Array of numbers.
 *
 *  a = Dvector[1, 5, -3]
 *  a.concat([6, 7])       -> Dvector[ 1, 5, -3, 6, 7 ]  
 *  a                      -> Dvector[ 1, 5, -3, 6, 7 ]  
 */ 
VALUE dvector_concat(VALUE x, VALUE y) {