Could we add an about button and page?

[fcbond]

Hi,

minimally, it would be good to have:

• who we are
• license
• citation
• link to source of lexicon interface and link to downloadable data

Ideally, we should also change the top left hand button to [SingDict] and have it link there (or to home).

I can mock up a page, but I struggle with npm, ...

[siewyeng]

closed with PR #20