Add markov-input highlight overlay on filedrag

Next up is making it slightly more attractive, i.e. transitions and
maybe a slight zoom in on the "Upload File"
Fix button class naming convention
Add upload file during drag on body (experimental)

Doesn't work right now, for some reason.
Fix dragover problem
Temporary: change to dragend listener to compare

Now there's no flickering on chrome, but an unsuccessful drag (i.e.
moving back to filesystem) results in the overlay staying there.
One idea is to make dragLeave conditional somehow?)
Add working drag js solution with 150ms delay

Not ideal, but it's what works for now. Still flickers a bit, I think,
if messing around with left column, but who actually will do that?
Fix buttonDone -> button-done class
Reduce README
Revert "Reduce README"

This reverts commit 658ce3d3f960e05492f76814a9f7719e7df82f18.
add .removeEventListener to dragOver

prevents drag over from being run again and again and again and again and again and again.
Add randomColorStyle.min.js

Prepare yourselves for spontaneity
Add random color support

Because, well, why not?
Merge branch 'more-ui-improvements' into gh-pages