Adds pid_file config.
Add to demo config
Merge branch 'hughbien-pid_file_config' into develop

* hughbien-pid_file_config:
  Add to demo config
  Adds pid_file config.
Fix annoying issue
Bump version
Merge branch 'develop'

* develop:
  Bump version
  Fix annoying issue
  Add to demo config
  Adds pid_file config.