Improve documentation a bit

[njvack]

Change references to original github URL to the one in the redcap-tools
organization.

Also tighten up the Installation section of index.rst -- we don't need
to care about the requests dependency, really. Mention the pandas
installation option.

Still TODO: Change the maintainer entry in setup.py.

[njvack]

The other thing that might be worth mentioning in the docs (or just in the README) is that this project is not affiliated with the official Project REDCap.

[pwildenhain]

Ah Darn, I also added a small contributing section to the README in #132 -- should that actually live in contributing.rst?

👍 For adding the maintainers list
👍 For mentioning this project is not offficial

[njvack]

I'd say that a small contributing section in readme is good (probably link to the one on readthedocs) -- I don't know that I'd think to check the docs for it otherwise.

[pwildenhain]

That makes sense, would you also be able to add that in this PR? Link out the the contributing.rst from the README? And then we'll likely need to update contributing.rst at some point haha

[njvack]

Yeah, that should be fine, it'll be a day or two, though; I'm on a lil vacation here.

[pwildenhain]

@njvack You've done good work here already, I'm just going to merge what you have. Feel free to submit another PR though if there is more you'd like to add.

[njvack]

Aww snap, thank you! I 100% forgot I had this outstanding :/