Add a pure-python version of the Black-Scholes function for comparison with the Cython equivalent
add name back into Cython Magics notebook
allow async output on the most recent request

Keeps track of the most recent request, so async output is still allowed
schedule async flush

allows threadsafe flush from background threads
Traits allow none
Added tests
try..finally for tearing down test
Add booktabs package to latex base.tplx
Implementation in TraitType directly.
Removed unnecessary print
Shut down kernels in parallel

When stopping the notebook server, it currently sends a shutdown request
to each kernel and then waits for the process to finish. This can be slow if
you have several kernels running. This makes it issues all the shutdown
requests before waiting on the processes, so shutdown happens in
parallel.

KernelManager (and MultiKernelManager) gain three new public API methods
to allow this:

* request_shutdown (promoted from a private method)
* wait_shutdown (refactored out of shutdown_kernel)
* cleanup (refactored out of shutdown_kernel)
Simplify KernelManager.cleanup()
Expose keyword arguments of KernelManager methods on MultiKernelManager
Rename wait_shutdown to finish_shutdown
When a preset is activated fire "preset_activated" event.
On "preset_activated" event, update the value of the maintoolbar select element that lists celltoolbar presets.
When a preset is registered after notebook is loaded, active it if needed.
Make sure that celltoolbars are hidden
when a notebook without "celltoolbar" entry in metadata is loaded.
Used **kwargs in initializers.
Merge pull request #5502 from Zaharid/iniinstance

Containers resolve instances (traits).
Fixed list validation
Fixed tuple