Use markdown citation and bibtex bibliography rather than hand drafting citations

[rpruim]

See #40 for another reference to this issue. Also #44.

Advantages of using a citation system:

• less duplication
• consistent formatting
• automatic link generation

Not sure if we need to use RMarkdown or whether the plain Markdown suffices.

There is already an example of this in pubs.Rmd

[rpruim]

I've made some good progress here. Notes:

• It appears that this only works when using Rmd or Rmarkdown (even though there isn't really any R involved).
• There is supposed to be an option of nocite: '@*' to make a bibliography of all items, but I can't get that to work. I wanted to add that to the resources page.

I'm using this now for a couple of the labs and intend to keep doing things this way going forward.

[rpruim]

The main to-do's here are

• [ ] remove need to use Rmarkdown (so web updates are less problematic, see #60)
• [ ] determine how to create multiple reference sections (using multiple bib files) on a single page.
• [ ] determine how to control the style of the references (in text and bibliography listing)