Addresses #42 and #63 -- adds pkgdown site and reorgs readme content

[stephhazlitt]

• addresses #63
• addresses #42
• reduce+edit readme
• fix issues with add_points vignette
• addresses #124

Aiming for "good enough" and definitely better than no pkgdown site 🤞

[stephhazlitt]

There are probably a few more nice things from @ateucher's PR #44 that could be ported over (like arranging the fxns in the ref list maybe?).

[boshek]

There are probably a few more nice things from @ateucher's PR #44 that could be ported over (like arranging the fxns in the ref list maybe?).

Probably good in a follow up. I say ship it!

[stephhazlitt]

Once approved, does adding a pkgdown site and re-org of doc content warrant a NEWS.md entry or no? I think maybe no 🤷‍♀️ .

[ateucher]

I think adding a news entry is good, it will help people find it