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
Used **kwargs in initializers.
Merge pull request #5502 from Zaharid/iniinstance

Containers resolve instances (traits).
Fixed list validation
Fixed tuple
Test for very large cells in latex

ipython#5616 (PDF from latex is hundreds of pages)
Silence exception thrown by completer when dir() does not return a list
implemented support for multiple channels in Audio
added docstring about multiple channel support in Audio
Merge pull request #5668 from minrk/async-output

allow async output on the most recent request
Merge pull request #5669 from minrk/flush-thread-output

allows threadsafe sys.stdout.flush from background threads