add ascii_only filter
require latex titles to be ascii

otherwise the ucs package barfs all over itself
set SO_LINGER=0 during port selection

might prevent EADDRINUSE errors in tests
use ipc for notebook js tests

on linux only

This ought to prevent EADDRINUSE errors in the kernel.
support extracted output in HTML template

allows

    ipython nbconvert --to html --ExtractOutput.enabled=True

to work properly without any b64-encoded data.
fix jpeg/jpg typo in ExtractOutput
add comment explaining null bytes in SO_LINGER
make input_area css generic to cells

removes otherwise-identical text_cell_input class in text cells
Merge pull request #5246 from ivanov/less-pylab

less %pylab, more cowbell!
Merge pull request #5209 from minrk/css

make input_area css generic to cells
Merge pull request #5245 from minrk/multi-file-html

support extracted output in HTML template
Merge pull request #5244 from minrk/test-ipc

try to avoid EADDRINUSE errors on travis
Merge pull request #5194 from minrk/ascii-latex-title

require latex titles to be ascii
adding visual play button
adding visual interrupt button
add toolbar highlighting on hover
try to have buttons render properly on nbviewer
a less jarring color
initial bootstrap tour

One way to get it to play currently is with a cell like this:

    %%javascript
    $.getScript('/static/notebook/js/tour.js')

provided that you have Bootstrap Tour installed in the components
fix typo for the location of bower.json