Plot windows should remember their position/size/autoscale

[philipstarkey]

Original report (archived issue) by Philip Starkey (Bitbucket: pstarkey, GitHub: philipstarkey).

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Plot windows should remember where they were last placed, the state of the autoscale button and their last size. Obviously they currently do this when new data comes in and the plot is updated, but they do not do it if lyse restarts, or the analysis script is removed and re-added.

This is useful if lyse crashes, or the analysis process crashes, as much of the restart time is spent setting up the plot windows, etc again.