A function that generates random pins (see as.pin). 
The generated pin is uniformely distributed over the time period.
Usage
rpin(
  n,
  start_date = "1900-01-01",
  end_date = Sys.Date(),
  p.male = 0.5,
  p.coordn = 0.1
)Arguments
- n
 number of observations. If
length(n) > 1, the length is taken to be the number required.- start_date
 Smallest possible
pin. Default is 1900-01-01.- end_date
 Largest possible
pin. Default is the current date.- p.male
 Proportion of males. Default is 0.5.
- p.coordn
 Proportion of coordination numbers. Default is 0.1.
