Merge pull request #2775 from ellisonbg/kernelid General cleanup of kernel manager code. This does some general cleanup of MultiKernelManager to better reflect how it is actually being used. Sometimes there is a need to create kernel_id's elsewhere in code. This minor change allows a kernel_id to be created outside of the MultiKernelManager and passed in as a kwarg. An exception is raised if the id is already used. Tasks: - [x] Fix cleanup of ipc files. - [x] Allow kernel_id to be passed to MultiKernelManager.start_kernel. - [x] Add ipc support to MultiKernelManager. - [x] Add more tests for MultiKernelManager. - [x] Rename sub channel to iopub channel everywhere. - [x] Use consistent naming for all channel classes in zmq, inprocess and qt. - [x] Move BlockingChannelMixin to zmq.blockingkernelmanager. - [x] Create ABC for KernelManager. - [x] Make the InProcessKernelManager a Configurable. - [x] Cleanup docstrings in ABCs. - [x] Add tests for KernelManager. - [x] Check over MultiKernelManager. - [x] Make KernelManager,kill_kernel private in ABC and implementations. - [x] Find bug that is causing the kernel manager tests to hang unless the shell channel linger is set to 0. - [x] Decide about critical logging in ipkernel. - [x] Debug lack of stderr redirect in tests.