Resume is one of the main feature since OS X 10.7 Lion. It’s a system-wide feature that allowing you to immediately get back to the exact state of the app even when system reboots. Use the following command to disable it.
defaults write NSGlobalDomain NSQuitAlwaysKeepsWindows -bool false
Restart your Mac or logout/in to make the changes appear.
The commands can be reversed with the command:
defaults write NSGlobalDomain NSQuitAlwaysKeepsWindows -bool true