Date checking tested
Fixed typo
Added tests for CellGrowth
Fixed date checking test
Merge branch 'feature/tests' of github.com:Derkje-J/programming-life into feature/tests
Added spec tests for CellGrowth and Substrate
Node fixed and fully tested
Added spectests to substrate
Merge branch 'feature/tests' of https://github.com/Derkje-J/programming-life into feature/tests
Improved Cell spec
Merge branch 'feature/tests' into develop