Polish up examples (somewhat)

- Mention them in the docs (arguably a bit hamfistedly).
- Make the README an RST.
- Make them pass flake8 and add flake8 to tox.ini

They should all be rewritten and made Python 3-friendly but that's out
of scope here.
diff --git a/examples/proxy.py b/examples/proxy.py
index b1c4253..3be26f9 100644
--- a/examples/proxy.py
+++ b/examples/proxy.py
@@ -8,15 +8,20 @@
 #
 # $Id: proxy.py,v 1.2 2004/07/22 12:01:25 martin Exp $
 
-import sys, socket, string
+import sys
+import socket
+import string
+
 from OpenSSL import SSL
 
+
 def usage(exit_code=0):
     print "Usage: %s server[:port] proxy[:port]" % sys.argv[0]
     print "  Connects SSL to the specified server (port 443 by default)"
     print "    using the specified proxy (port 8080 by default)"
     sys.exit(exit_code)
 
+
 def main():
     # Command-line processing
     if len(sys.argv) != 3:
@@ -26,12 +31,13 @@
 
     run(split_host(server, 443), split_host(proxy, 8080))
 
+
 def split_host(hostname, default_port=80):
     a = string.split(hostname, ':', 1)
     if len(a) == 1:
         a.append(default_port)
     return a[0], int(a[1])
-    
+
 
 # Connects to the server, through the proxy
 def run(server, proxy):
@@ -66,5 +72,6 @@
 
         print buff,
 
+
 if __name__ == '__main__':
     main()