WIP
Adding underscore.js
Updating data.js with Katsuo's spreadsheet

Result: get all kanji-keyword pairs from editions of RTK vols. 1 and 3.
Why? So that a user can get max coverage with Heisig without having to
paste all the kanji they know.
Selecteable and highlighteable
Delete recognized kanji. Inline-block recogs.
Kanji list works. Nicer presentation via H1/H2!
Clang-format