upgo_scrape_kj: Function to scrape Kijiji listings
In UPGo-McGill/upgo: Utility Functions for UPGo Lab Members

upgo_scrape_kj scrapes all data from Kijiji rental listings in Montreal, Toronto or Vancouver.

upgo_scrape_kj(
  city,
  old_results = NULL,
  short_long = "both",
  recovery = FALSE,
  proxies = NULL,
  quiet = FALSE
)

`city`	A character vector indicating the city or cities to scrape. Currently accepts "montreal", "toronto" or "vancouver" as inputs.
`old_results`	A data frame. If the output of a previous run of `upgo_scrape_kj` is supplied, listings previously scraped will be incorporated into the new results.
`short_long`	A character scalar. Should short-term rentals ("short"), long-term rentals ("long") or both ("both", the default) be scraped?
`recovery`	A logical vector. Should the function attempt to recover results from a previous, unsuccessful function call?
`proxies`	Character vector of IPs to use for proxy connections. If the length is less than the number of processes set by 'future::plan()', proxies will be recycled.
`quiet`	A logical vector. Should the function execute quietly, or should it return status updates throughout the function (default)?