Do not display repeated lines by default

[raspi]

% python -c "print('01234567' * 10,end='')" | heksa -w 8 
000000┊30 31 32 33 34 35 36 37┊01234567
000008┊30 31 32 33 34 35 36 37┊01234567
000010┊30 31 32 33 34 35 36 37┊01234567
000018┊30 31 32 33 34 35 36 37┊01234567
000020┊30 31 32 33 34 35 36 37┊01234567
000028┊30 31 32 33 34 35 36 37┊01234567
000030┊30 31 32 33 34 35 36 37┊01234567
000038┊30 31 32 33 34 35 36 37┊01234567
000040┊30 31 32 33 34 35 36 37┊01234567
000048┊30 31 32 33 34 35 36 37┊01234567

Would become something like:

000000┊30 31 32 33 34 35 36 37┊01234567
-- line repeated 8 times (N bytes) --
000048┊30 31 32 33 34 35 36 37┊01234567