In atreus-view convert keys to their symbol or name

There's probably room for improvement, but this works.

One edge case was that returning a `|` got interpreted as a table cell delimiter by org mode, and using either HTML entity `&#124;` or the [org-symbol](http://orgmode.org/worg/org-symbols.html) `\vert{}` failed to render correctly in the HTML.

I left the `(if (listp key)…)` at the end just in case there's other shifted characters that I missed. I imagine if people want to assign other punctuation that would normally need to be shifted in QWERTY, then there will be more combinations for those keys.