ccnxmn is an extension of Mininet

Changes:
1/- setup.py is modified
2/- new directory "ccnxmn" is created with 4 new files:
  - __init__.py
  - CCN_cli.py
  - CCN_node.py
  - conf_parser.py
3/- bin/miniccnx is changed
-from mininet.cli import CLI
-from mininet.node import CPULimitedCCNHost, CCNHost
+from ccnxmn.CCN_cli import CCNxCLI
+from ccnxmn.CCN_node import CPULimitedCCNHost, CCNHost

-from mininet.conf_parser import parse_hosts,parse_routers, parse_links
+from ccnxmn.conf_parser import parse_hosts,parse_routers, parse_links

-    CLI(net)
+    CCNxCLI(net)