subprocess iostreams only send on flush
cleanup unused symbols in iostream

and add docstring / copyright
resolve rebase conflict

s/sub_channel/iopub_channel/
workaround Windows lack of fork in subprocess tests

simple Process(target=f) doesn't work for interactively defined f.
allow disabling subprocess pipe
disable subprocess pipe in inprocess kernel

because it isn't using zmq anyway
subprocess outstream forwarding doesn't work on Windows
add mission io
flush on newline in subprocesses

reduces issues with mp.Pool
allow adjustable subprocess flush limit
ignore error waiting for pipe flush message
Fix inprocess_qtconsole example
`IPython.zmq` --> `IPython.kernel.zmq` throughout docs and examples
Merge pull request #2878 from robyoung/master

Pass host environment on to kernel
Merge pull request #2880 from mspacek/inprocess

update examples and docs after kernel move

mostly just s/zmq/kernel.zmq/ and s/inprocess/kernel.inprocess/ changes.
Merge pull request #2877 from Carreau/minor-css-fixes

minor css fixes, forgotten ";" and remove commented rules.
Merge pull request #2868 from takluyver/import-performance

Import performance

Defer various imports for a small reduction in startup time.

IPython.lib.__init__ previously loaded IPython.lib.inputhook to export some of its functions. This meant that importing anything from IPython.lib also loaded inputhook.

For now, I've just removed that import, but that is an API change, because the functions are no longer accessible as e.g. IPython.lib.enable_qt4

Added a note about the API change.

Timing command, borrowed from Openoffice to simulate cold start:

$ sync ; echo 3 | sudo tee /proc/sys/vm/drop_caches; time ipython3 -c pass

Results with this branch: 7.68, 7.64, 7.35, 7.38 s 'real'
Results with master: 8.17, 8.04, 7.81, 7.77
Merge pull request #2819 from minrk/qt_hist_up

tweak history prefix search (up/^p) in qtconsole

moving the cursor around the line could result in weird inconsistencies in the prefix.

This simplifies the logic by always using the cursor position to set the history prefix, and better determine when the history prefix has actually changed.

also fixes a small typo where a while-loop was always checking the initial value, rather than the iterator, which could result in an IndexError at the end of the history.

closes #2485
fix button css
remove one useless element