AM: print only a few digits for DIIS coeffs

Othewise the line is too long.
AM: print waringin only once
AM: whitespace, comments
AM: expanded form use dashes
AM: accept (~ ("path" "X" "Y")) form for basis maps

Example for uranyl with arbitrary many waters and two types of oxygen:

    (~ ("U_24.19.16.11_10.7.7.4" "U")
       ("O_9.5.1_5.4.1" "O" "OW")
       ("H_6.1_4.1" "HW"))