Refactoring: removed redundant SimulationState
Began adding weight-updating functionality.
Completed part of weight-updating. Still need to add regeneration of
agents when max weight is reached.
Added new end2end test for regeneration of an agent after reaching max
weight.
Revert "Added new end2end test for regeneration of an agent after reaching max weight."

This reverts commit 14d0bfc4b00af52bc0c492620e4dda7f15ff4de7.