URI constructor

Function that is called in a carbon object to construct valid uri to send to browser

.uri(self, private, code)

Arguments

self	carbon self object
private	carbon private object
code	character, script to embbed into the uri

if(interactive()){

x <- carbon$new('x <- 1')

# populate from self$code
x$uri()

# enter manually
x$uri(code = 'x <- y + 3')

}