Optimization keeps running when page is left or reloaded

[nesnoj]

To free the CPU thread the optimization should be cancelled.
Maybe use JS' beforeunload to notify the backend?

[nesnoj]

Another question on this @henhuy: If an optimization is running and I go back to settings, change a param and again forward to results, is a second one started for that very same user? So quickly repeating this 10 times will start 10 processes?

[henhuy]

Unfortunately, yes. And it's even worse, that after two simulations with same parameters are stored, loading a simulation with given parameters leads to an internal error, as Django expects a single result from query instead of multiple rows... :(

[nesnoj]

Fixed in #377