ipunch: ipunc in Chim, ipun in Gasworks

 Gasworks plot file formats to which we are unaccustomed:
    ipunch = 1
    ipunch = 2


 Gasworks plot file formats analogous to ipunch = 1, 2 in Chim-xpt:
    ipunch = 3 prints the three line header at the top,
                the standard data blocks, and
                automatically changes 3 to 4
    ipunch = 4 prints only the standard data blocks