1. Use strtoX instead of stringstream in stringToInteger since it
   is about 20x faster.
2. Fix scons .
- accomodate header rename
Add support for headless vrouter.
In headless vrouter, even after death of all control nodes, agent does not flush
off configs/routes and continue to work with last known good configuration
(which is the information sent by last stable control node).
The information is amrked as stale and agent continue working with same.
When a new control node comes up agent will flush off the stale data and use the
information sent from new control node. Flushing of data is timer based so that
instability of new control node can be handled and due time can be given to
exchange the information (config + route paths).
Along with headless mode changes, non headless mode has been retained. Though by
default agent works in headless mode.

Other than headless mode this commit also caters to re-org of controller
subscription code in agent which essentially involves using common route walker.
Compute tunnel_type_ in route path for VGW routes.
Update provision_vgw_interface.py to sent thrift message
Merge pull request #659 from praveenkv/master

Compute tunnel_type_ in route path for VGW routes.
Merge pull request #650 from Juniper/fix

- accomodate header rename
backward compatibility of contrail-analytics-api
Merge branch 'master' into ted-opsvr
Limit the number of flows per VM based on agent configuration
make max_vm_flows as a % of overall flows
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
Use interface-name instaed of interface-index when deleting vgw interface
in provision_vgw_interface.py script
Merge pull request #664 from praveenkv/master

Use interface-name instaed of interface-index when deleting vgw interfac...
Interface and VRF are mandatory arguments only for VGW create
Merge pull request #665 from praveenkv/master

Interface and VRF are mandatory arguments only for VGW create
fix test case build error
Merge pull request #662 from haripk/master

Limit the number of flows per VM based on agent configuration
Merge pull request #647 from Juniper/meghb_stoi

1. Use strtoX instead of stringstream in stringToInteger since it
Merge pull request #661 from Juniper/ted-opsvr

opsvr: backward compatibility of contrail-analytics-api