The problem was that when you start vim like "vim foo.cc", the FileReadyToParse
event is sent to the server before it's actually started up. Basically, a race
condition.
We _really_ don't want to miss that event. For C++ files, it tells the server to
start compiling the file.
So now PostDataToHandlerAsync in BaseRequest will retry the request 3 times
(with exponential backoff) before failing, thus giving the server time to boot.
These happen rarely and are not a big deal when they do. We still log them to
the Vim message area, but we don't annoy the user with the default, in-your-face
Python traceback.
