Suppress $cse variables in the OMEdit Variables Browser

[casella]

In case the backend generates $cse variables, they are shown first in the Variables Browser, which is totally weird for normal users who don't even have a clue what they are.

They should be suppressed, possibile enabled optionally and in that case shown at the end of the variable list, not at the beginning.

[adeas31]

@casella can you attach a test model so I can investigate this more.

[casella]

I tried with the attached model, which shows $cse1 in the debugger, but in fact $cse1 does not appear in the Variables brower. Maybe this problem was solved in the meantime, or these variables only appear in other cases. Unfortunately I can't remember what I was working on when I opened this, sorry about that.