Merge pull request #2077 from rblomberg/yahoo-csv-url-fix

changed URL to the current CSV API for yahoo finance
Added a wider range of day ranges for the AutoDateLocator.
Update pie_demo_features.py

line break added before "plt.show()" line
Update spines_demo.py

Line break added before "plt.show()"
Merge pull request #2100 from glyg/master

Remove DeprecationWarning in simple_linear_interpolation
Skip the pep8 conformance test when the pep8 tool is not installed
Merge pull request #2103 from mdboom/pep8-skip-when-pep8-not-installed

Skip the pep8 conformance test when the pep8 tool is not installed
Fix 64 bit compatibility on Windows

Use `Py_ssize_t` (64 bit on win-amd64) instead of `C long` (32 bit on win-amd64) to handle `pointers` (64 bit on win-amd64).
Merge pull request #2107 from cgohlke/patch-1

Fix 64 bit compatibility on Windows
fix position of rotated mathtext in agg backend
Fix exception_to_str to work on Python 2.x
If multiprocessing fails, don't use it during setup.
Make setup work on platforms where multiprocessing does not.
Merge pull request #2111 from leejjoon/fix-text-position-agg-backend

fix position of rotated mathtext in agg backend
Merge pull request #2104 from mdboom/exception_to_str

Bug in cbook.exception_to_str() in v 1.2
Don't draw bottom line of histogram when it is unfilled.
Merge remote-tracking branch 'upstream/v1.2.x' into v1.3.x
Merge remote-tracking branch 'upstream/v1.3.x'
Merge pull request #2113 from mdboom/histogram-step-unfilled-bottom-line

hist() bottom line now showing (regression?)
Merge pull request #2083 from pelson/longer_date

Added a wider range of day ranges for the AutoDateLocator.