Move ipkernel to kernelbase module
Restore ipkernel module
Separate IPython kernel implementation from kernel machinery
Stub out kernel methods to allow overriding a subset of them.
Document how to create wrapper kernels
Fix for using Type traitlet
Allow Type trait to be set with an importable string
Fix some assumptions in kernelapp
Add example of a simple kernel
Pass history request keys as **kwargs
Inspection -> introspection for doc consistency
Rename KernelBase & Kernel to Kernel & IPythonKernel
Merge branch 'kernelbase' of github.com:takluyver/ipython into kernelbase
Merge pull request #5951 from takluyver/kernelbase

Refactor kernel base class which can be inherited for wrapper kernels