prnt command: add option --multiColumns

[mattirn]

displays the collection of simple values in multiple columns.

Example:

groovy-repl> 
groovy-repl> keymap |; prnt --multiColumns
"^@" set-mark-command                    "^A" beginning-of-line                   "^B" backward-char                       
"^D" delete-char-or-list                 "^E" end-of-line                         "^F" forward-char                        
"^G" abort                               "^H" backward-delete-char                "^I" expand-or-complete                  
"^J" accept-line                         "^K" kill-line                           "^L" clear-screen                        
"^M" accept-line                         "^N" down-line-or-history                "^O" accept-line-and-down-history        
"^P" up-line-or-history                  "^R" history-incremental-search-backward "^S" history-incremental-search-forward  
"^T" transpose-chars                     "^U" kill-whole-line                     "^V" quoted-insert                       
"^W" backward-kill-word                  "^Y" yank                                "^]" character-search                    
"^_" undo                                " "-"(" self-insert                      ")" insert-close-paren                   
"*"-"\\" self-insert                     "]" insert-close-square                  "\^"-"|" self-insert                     
"}" insert-close-curly                   "~" self-insert                          "^?" backward-delete-char                
.......