Element types in BDSim survey outputs

[untitled-angoose]

The element "Type" column is not filled for rmatrix, thinrmatrix and rfcavity (fringe field) elements in BDSim survey outputs (see attached files).

RFCavityTests.gmad.txt
TestBDSimSurvey.dat.txt

This disrupts code designed to read from BDSim survey files, such as pybdsim.Data.Load, as they do not parse the unfilled column correctly.

I think a simple fix would be to make the GetType method return "None" or NaN for a BDSim element that has no type set - so the "Type" survey column is always filled.

[stewartboogert]

Can you put this issue on the pybdsim repo https://github.com/bdsim-collaboration/pybdsim/issues

[lnevay]

See PR #119