Create prior default method
# S3 method for default
createPrior(x, wt, ...)
a vector of x values at which the prior is to be specified (the support of the prior). This should contain unique values in ascending order. The function will sort values if x is unsorted with a warning, and will halt if x contains any duplicates or negative lag 1 differences.
a vector of weights corresponding to the weight of the prior at the given x values.
optional exta arguments. Not currently used.
a linear interpolation function where the weights have been scaled so the function (numerically) integrates to 1.