overloaded `_make_twin_axes` on `LocateableAxesBase` so that twinx and
twiny will work.
Added new-style formatter function.

Added class `StrMethodFormatter` which is identical to `FormatStrFormatter`
only for new-style ('{}'.format) formatting methods.
BUGFIX: ensure that number of classes is always of type INT in Colormap
Axes.plot: remove set_default_color_cycle from the docstring

It has been removed in 2c24a7c13645fbf0c79bb102274604c3f37b70d2.
Merge pull request #2639 from bulli92/master

BUGFIX: ensure that number of classes is always of type INT in Colormap
pep8 fixes
Merge remote-tracking branch 'upstream/v1.3.x'

Conflicts:
	lib/matplotlib/axis.py
	lib/matplotlib/tests/test_axes.py
put in explicit field name for 2.6 compatibility.
Merge pull request #2640 from mineo/plot-docstring

Axes.plot: remove `set_default_color_cycle` from the docstring as the function has been depreciated and removed (2c24a7c)
Merge pull request #2503 from mdboom/fix-interactive

Fix interactive mode detection
removed izip import which was blowing up the python 3.x builds
Merge pull request #2461 from tacaswell/new_style_format_str

Added a new style string Formatter.
Small typo in the license.
Added option to show/hide Source link in plot_directive
Added html to option name
Merge pull request #2644 from arokem/license_typo

Small typo in the license.
Update backend_webagg.py

Change WebAgg backend to handle stale figure UI controls in the browser
Update mpl.js

We are generating 'ReferenceError: figure is not defined' when we try to download a figure into a particular image type.
Merge pull request #2645 from loicseguin/show-source-link

Add option to show/hide the source link in plot_directive
plot_date: Set the default fmt to 'o'

Different to just plot() plot_date() has a default plot format string
which makes it necessary to *unset* the default one when drawing
multiple sequences of dates in a figure to get a working color cycling.
It also was not exactly clear that Axes.set_color_cycle was setting the
color cycle for every plot command except for plot_date ones.

It was of course possible to simply unset it after reading the
documentation but that's not the path of least suprise.

The default fmt of 'o' will keep the markers by default (which makes
sense for dates) but allows color cycling to happen.

This is related to issue #2148