Generate doc using rebar3_ex_doc

[kianmeng]

List of other changes:

• remove trailing spaces
• missing missing date to changelog
• add badges for quick overview

Screenshot:

[choptastic]

I man, I just realized I started the "code review" comments here, but never submitted them.

If you're willing to update this, I'd love it, and if not, I can do it, since it's been sitting here for so long because I don't know how to use github, apparently.

Thanks!

[kianmeng]

@choptastic I can't seem to get this to work on my local environment with recent rebar3_ex_doc, see jelly-beam/rebar3_ex_doc#60. Maybe it will work on your environment?

[choptastic]

Hi @kianmeng , you're right, I'm experiencing this as well.

If I have some time tonight, I may cut my elixir teeth and tinker with this to see if I can troubleshoot it.

Very interesting problem.

[kianmeng]

@choptastic I believe there is a fix for it, see jelly-beam/rebar3_ex_doc#60 (comment)

[choptastic]

Excellent! I did indeed see that. Thanks again!

[choptastic]

Oh, and thank you for making those small corrections. I will merge them in.