add venn 2~6 and demo

demo.py

@@ -0,0 +1,37 @@
+# coding: utf-8
+
+# ipython notebook requires this
+# %matplotlib inline
+
+# python console requires this
+import matplotlib
+matplotlib.use('Agg')
+import matplotlib.pyplot as plt
+
+import venn
+
+labels = venn.get_labels([range(10), range(5,15)], fill=['number', 'logic'])
+fig, ax = venn.venn2(labels, names=['List 1', 'List 2'])
+fig.savefig('venn2.png', bbox_inches='tight')
+plt.close()
+
+labels = venn.get_labels([range(10), range(5, 15), range(3, 8)], fill=['number', 'logic'])
+fig, ax = venn.venn3(labels, names=['list 1', 'list 2', 'list 3'])
+fig.savefig('venn3.png', bbox_inches='tight')
+plt.close()
+
+labels = venn.get_labels([range(10), range(5, 15), range(3, 8), range(8, 17)], fill=['number', 'logic'])
+fig, ax = venn.venn4(labels, names=['list 1', 'list 2', 'list 3', 'list 4'])
+fig.savefig('venn4.png', bbox_inches='tight')
+plt.close()
+
+labels = venn.get_labels([range(10), range(5, 15), range(3, 8), range(8, 17), range(10, 20)], fill=['number', 'logic'])
+fig, ax = venn.venn5(labels, names=['list 1', 'list 2', 'list 3', 'list 4', 'list 5'])
+fig.savefig('venn5.png', bbox_inches='tight')
+plt.close()
+
+labels = venn.get_labels([range(10), range(5, 15), range(3, 8), range(8, 17), range(10, 20), range(13, 25)], fill=['number', 'logic'])
+fig, ax = venn.venn6(labels, names=['list 1', 'list 2', 'list 3', 'list 4', 'list 5', 'list 6'])
+fig.savefig('venn6.png', bbox_inches='tight')
+plt.close()
+