1.7.4 Resource leak

[Kilinich]

I think problem with lags is related with dynamic properties.
I've create scene with only 24 circles and set dynamic collideSet (depend on some variables), and it runs fine.
Then I just re-open that scene few times (not exit from app) and Algodoo slow down to 10 % realtime...

That explain performance degrade on most of my scenes in 1.7.4