Merge branch 'epatters-qtfrontend' into kernelmanager

Cleanup of the XREQ channel. * Removed dead handler code. * Simplified things.

Merge branch 'kernelmanager' of git://github.com/ellisonbg/ipython into qtfrontend

Fixed high CPU usage of XREQ channel. Previously, the XReqSocketChannel was consuming nearly 100% CPU. This was caused by the ioloop polling for POLLIN|POLLOUT|POLLERR always. Now we are only polling for POLLOUT when there is a message waiting to be sent. This seems to have fixed the problem.

SUB channel _handle_recv is now greedy. This change is needed so that a single ioloop iteration will handle all of the messages that have been received. Otherwise the ioloop has to run multiple time to get everything.

Added initial draft of blockingkernelmanager.py.

General cleanup of kernelmanager.py. * Old handlers code removed. * Comments added.

Channels can no longer be restarted.

Changing -1=>0 for bind to random ports.

* Fixed history breakage due to recent refactoring. * Minor documentation and cleanup.