Config Changes for thinning of Neutron Plugin

- Added extension code to handle neutron requests for network API
- config_db from neutron is moved to neutron_plugin_db.py in config-extensions
- neutron_plugin_interface.py handles the plugin API requests in cfgm
Merge pull request #663 from Juniper/praneet_new_ncompat

Config Changes for thinning of Neutron Plugin
Schema changes for port api
Merge branch 'config-devel' of github.com:Juniper/contrail-controller into config-devel
get_network and get_network_count now use the /neutron/network URL
Merge pull request #682 from Juniper/praneet_new_ncompat

get_network and get_network_count now use the /neutron/network URL
removed unnecessary bottle callbacks
Merge pull request #687 from Juniper/praneet_new_ncompat

removed unnecessary bottle callbacks
Config/control node changes to support port changes
Added support in backend for subnet thinning
Merge pull request #694 from Juniper/praneet_new_ncompat

Added support in backend for subnet thinning
Merge pull request #701 from Juniper/config-devel

Config devel