Add new_member.py example to showcase messaging new members.

examples/new_member.py

@@ -0,0 +1,18 @@
+import discord
+
+client = discord.Client()
+client.login('email', 'password')
+
+@client.event
+def on_member_join(member):
+    server = member.server
+    client.send_message(server, 'Welcome {0} to {1.name}!'.format(member.mention(), server))
+
+@client.event
+def on_ready():
+    print('Logged in as')
+    print(client.user.name)
+    print(client.user.id)
+    print('------')
+
+client.run()