Large models crashing when Network analysis runs

[martac]

In some cases, when the ecopath model is large or has some multi-stanzas, if you go to ecopath, tools, network analysis and run some analysis, the program starts computing but freezes and ends up crashing at the end. This happens with models that were originally build with v5 and were translated into 6. Some of these models are: ainsworth 5, ainsworth 6, Bullman 1, Bullman 2, Freire 1, Mohamed 2, Velasco 1 (all from the Biomass Regression database) and some models from Okey (2004, 2001) and Bundy (2005). I think this is only a problem for models that were translated from v5 to v6, but I am not sure.

[jeroens]

The Lindeman calculations take a very long time to complete, but may get stuck in a loop. A solution is two-fold:

• Fix any deadlock in the Lindeman calculations
• Add a means to stop the calculations via the User Interface

[jeroens]

Related to #1133