add sympy support; which can transfer your network into sympy expression;

add visualize in genome;
add related tests.

tensorneat/examples/interpret_visualize/visualize_genome.py

@@ -0,0 +1,13 @@
+import networkx as nx
+import matplotlib.pyplot as plt
+
+# 创建一个空白的有向图
+G = nx.DiGraph()
+
+# 添加边
+G.add_edge('A', 'B')
+G.add_edge('A', 'C')
+G.add_edge('B', 'C')
+G.add_edge('C', 'D')
+
+# 绘制有向图