Marshal all data into single file

[sim642]

In #354 it became apparent that separately marshaling loses some connections or duplicates some data between the files. See
#354 (comment), #354 (comment) and #354 (comment).

Hence it would make more sense to marshal everything (solution, solver hashtables, analysis auxiliary data, etc) connected and unduplicated in a single record.
We can still have options then controlling what is and isn't marshaled and just have them optional in the record. But if they're all present, they should all relate properly.

Probably to be done after #356 and #350, which both change what and where is marshaled.

[sim642]

Another reason to do this is #731 (comment).