[ANN] Telperion.jl - Macro Magic for Properties and Statistical Formulas

@Mason has something similar to @with in StatidModules.jl. It works in I think the same way.

Another note is that in general, when you use @withprops with DataFrames, Julia won’t be able to write very performant code, since Julia doesn’t know from the type of df which symbols it encounters are in the data frame.