Add helper for quitting Nvim from the client

Also fix the error type raised when the connection is closed to IOError

Author: tarruda

neovim/api/nvim.py

@@ -175,6 +175,20 @@ def err_write(self, msg):
         """Print `msg` as an error message."""
         return self._session.request('vim_err_write', msg)
 
+    def quit(self, quit_command='qa!'):
+        """Send a quit command to Nvim.
+
+        By default, the quit command is 'qa!' which will make Nvim quit without
+        saving anything.
+        """
+        try:
+            self.command(quit_command)
+        except IOError:
+            # sending a quit command will raise an IOError because the
+            # connection is closed before a response is received. Safe to
+            # ignore it.
+            pass
+
 
 class Current(object):
 

neovim/msgpack_rpc/event_loop/base.py

@@ -159,7 +159,7 @@ def _on_signal(self, signum):
 
     def _on_error(self, error):
         debug(error)
-        self._error = Exception(error)
+        self._error = IOError(error)
         self.stop()
 
     def _on_interrupt(self):