Add common exit methods

include/gmon.py

@@ -103,5 +103,12 @@ class App:
         path = os.environ.get("GMON_PLUGINS", path)
         self.pluginpath = path
 
+    def die(self, msg, rv=9):
+        sys.stderr.write(msg + "\n")
+        self.exit(rv)
+
+    def exit(self, rv=0):
+        sys.exit(rv)
+
     def run(self):
         print self.subcommand.get_output()