fix test compilation error
refactor loadCortex into its own method
add ability to load cortex from url
Revert "Initialize neural net such that it starts with weights that make it play at the same level as a minimax bot."

This reverts commit e41a26058336dde91a5231cf5391ff95d3ca0f79.
set bias starting values to 0
add sensorFuncPieceDifferential()