We import the scripts from ycmd with a couple of modifications:
- don't set YCM_CORES=1 as we didn't before, and this makes the build a lot faster
- don't install gcc-4.8 as we didn't before
- install argparse as it is not available in python2.6
The server is multi-threaded and will spawn a new thread for each new request.
Thus, the completers need not manage their own threads or even provide async
APIs; we _want_ them to block because now were implementing the request-response
networking API.
The client gets the async API through the network (i.e., it can do something
else while the request is pending).
