Implements division of cells, closes #9

	modified:   cellular_automata/cells/base.py
	modified:   cellular_automata/cells/regular.py
	modified:   cellular_automata/lattices/equiangular.py
	modified:   cellular_automata/rules/base.py
Updates tests

	modified:   test/cellular_automata/cells/test_regular.py
	modified:   test/cellular_automata/lattices/test_equiangular.py
	modified:   test/cellular_automata/rules/test_basic.py
Changes settings of example

	modified:   variable_equangular_test.py