• [feature] Added signals: config_status_changed, checksum_requested, config_download_requested
• [feature] Added the possibility of specifying default values for variables used in templates
• [feature] Added banner_timeout
• [feature] Emit signal when DeviceConnection.is_working changes
• [change] Backward incompatible change: the config_modified
  signal is not emitted anymore when the device is created
• [change] VPN files now have 0600 permissions by default
• [change] Increased minimum netjsonconfig version to 0.8.0
• [change] Increased minimum paramiko version to 2.7.1
• [change] Increased minimum celery version to 4.4.3
• [fix] Avoid errors being hidden by tabs
• [fix] Fixed clashes between javascript schema validation and variables
• [fix] Fixed exception when adding device credential without type
• [fix] Fixed exception when auto adding device credentials to devices which don't have a configuration
• [fix] Avoid multiple devices having the same management IP address (multiple devices
  having the same last IP is allowed because last IP is almost always a public address)
• [docs] Documented SSH timeouts
• [docs] Update outdated steps in README instructions