lineedit: handle Ctrl-arrows

lineedit: handle Ctrl-arrows

function                                             old     new   delta
read_line_input                                     4629    4824    +195
BB_isalnum                                             -      39     +39
BB_ispunct                                             -      35     +35
BB_isspace                                             -      31     +31
static.esccmds                                        69      93     +24
vi_word_motion                                       165     162      -3
vi_back_motion                                       204     198      -6
vi_end_motion                                        172     163      -9
bb_iswspace                                           28       -     -28
bb_iswpunct                                           32       -     -32
bb_iswalnum                                           37       -     -37
------------------------------------------------------------------------------
(add/remove: 3/3 grow/shrink: 5/8 up/down: 334/-129)          Total: 205 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>