Watchdog for GroupVPN

 - When TinCan does not respond it kills the process and restarts
   it
 - When TinCan fails consecutively more than three times, it
   terminates itself.
Minor correction on WatchDog and gvpn_controller

 - Corrected all pointed out watchdog and gvpn-controller code
Separate Watchdog from GoupVPN Controller

Previously I extended GroupVPN class and added watchdog features.

Now, watchdog is a separate class and have a separate socket interface with
TinCan.
deleted not used codes
deleted not-used codes
Changed wait time back to 30s from 0.3

The reason I used 0.3 is to make the thread more interactive.

(Just to make the thread terminate within 0.3 when I ctrl+c)

But the actual reason the ctrl+c didn't work on thread was I didn't

properly set the thread as daemon.
Set the watchdog port to 0

To dynamically assign port number, changed the port number to 0.
Moved sample_config.json to root
Merge pull request #4 from kyuhojeong/qho

Separate Watchdog from GroupVPN Controller