Ecospace maps do not draw maps correctly

[joeb]

Under conditions where Ecospace has been run for long periods of time, with larger models, it can fail to plot some of the maps correctly. To recreate this it may require making multi runs and changing the map frequently. When this is occurring the plot will all be blue, like there was no change in the data.

[jeroens]

This only occurs in our particular case, where map drawers run out of memory if used to write PNG images to file. This has been fixed