add to pages: lubridate

[RhoBott]

Time data is notoriously complicated + variably formatted; lubridate is great at dealing with it, and also -- folks who are using our pages as their springboard to R might not know this exists.

I'm not sure where in our documentation this fits or entirely how to scope this; adding here to start the conversation.

Some things we might wish to add:

• link to a cheatsheet
• clear instructions on loading (it's part of The Tidyverse, but is it part of library(tidyverse)?)
• worked examples of a couple of functions that seem relevant to student/faculty work ((Main use that comes to mind for me is matching GPS/time data with environmental chemistry/time data; can share the most recent iteration of this w/ folks who are curious))
• surely other things; this is a start!

[simonpcouch]

Totally on board for having something re: lubridate around.

One observation which may not hold for others... I mostly use lubridate when I'm plotting---getting axes to format properly / trying to extract more or less discrete units of time to visualize. Is this others' experience? If so, maybe a home for brief mention + explanation could be in the plotting sections. If not so, ignore. :-)