Issue I427 [81,enhancement,example,mostlyresolved] New multipole expansion cofficient calculation example. The "multipole_expansion" example calculates the multipole expansion from potentials defined analytically or in a SIMION PA. NOTE: This is currently an 8.1 feature that is only available in the 8.1 "early access" mode. See Issue I421 for details. NOTE: equation in paper not correct. See README file. Added in 8.0.4-TEST10 (for 8.1).