feature: ascii dump together with hex dump

[pokanoka]

Feature request.
On the website hexdump is displayed on the right hand side. To quickly identify certain data regions it would be very nice to also have ascii dump there, as in classic hex editors.

My personal preference for non-printable characters: attempt to display them. E.g. \x01 is classical face, \x06 is pike, etc (but definitely not their colored emoji replacements ☺). That said, just displaying dot or space in place of unprintable chars is okay alternative. Substitute for \x00 should probably be space, if anything to make UTF-16 strings in the data look more clean.