As I use SIM on several computers and wantet to escape the hassle of copying my history back and forth, I decided to write a small tool that can merge the history of two installations. Currently its a proof-of-concept implementation 
that will merge the SIM history files from two given directories into a third directory whose contents you can then copy over both installations.
Please find the source at historyMerge.cpp (after it has been moved there, capi: i could not upload the file or copy it there, so it’s still im my home-directory)