/*
 *  call-seq:
 *     Dvector.read_rows(filename, dest, start=1)  ->  array of dvectors
 *
 * The data on the file should be organized in rows of numbers, with one row per line.
 * The rows need not all have the same number of entries since each row is placed in its own Dvector.
 * The _start_ parameter determines the starting line and defaults to 1 meaning start at the first line of the file.
 * The _dest_ must be an array with entries either Dvectors or <code>nil</code>.  For entries that are Dvectors, the
 * contents of the vector are replaced by the row of data from the file.  The _start_ row is placed in the
 * first entry in _dest_, the second row in the next, and so on.  If the entry in _dest_ is <code>nil</code>, that row of the file is skipped.
 *
 */ 
VALUE dvector_read_rows(int argc, VALUE *argv, VALUE klass) {