Run tests with tape, fix errors and update links in docs

[watilde]

Hello,

Here is the summary what I do in this PR:

• Run tests with tape when npm test is executed
• Fix the errors in the tests
• Fix the links in the docs and index.html

All of these are just tweaks so I've put them all to a single PR. Thanks.

[watilde]

Ok, I've replaced the update with the better demo code :)

[danfinlay]

Very nice, thanks!