Add example to TTY documentation

doc/api/tty.markdown

@@ -2,6 +2,19 @@
 
 Use `require('tty')` to access this module.
 
+Example:
+
+    var tty = require('tty');
+    tty.setRawMode(true);
+    process.stdin.resume();
+    process.stdin.on('keypress', function(char, key) {
+      if (key && key.ctrl && key.name == 'c') {
+        console.log('graceful exit');
+        process.exit()
+      }
+    });
+
+
 
 ### tty.open(path, args=[])