MMB freezes when GPM6_IMF13 comparison is made with all possible rules

[btatar13]

Describe the bug
GPM6_IMF13 crashes if comparison is made with all rules as it seems that it is too much for Matlab. Model is huge. Actually, I don't think so that we can do much about it, or can we?

To Reproduce
Steps to reproduce the behavior:

1. Compare GPM6_IMF13 with all possible rules

Desktop (please complete the following information):

• Win10
• Matlab 2019a
• Dynare 4.5.7

[gboehl]

Nope. One could do some automated crash handling, but I really don't think we should give that any priority.

[j2L4e]

I don't think it crashes, it just takes a REALLY long time because the model has so many variables. JSON serialization is quite slow but I think it's the only relatively-trivial option we have (thanks to jsonlab). I'd expect saving a .mat file and parsing that on the electron side to be orders of magnitude faster for large datasets but it doesn't seem worth the effort