Post review with Min, Fernando, and Brian.  Simplification
	deleted:    latex/abstract.tplx
	deleted:    latex/latex_sphinx_article.tplx
	deleted:    latex/latex_sphinx_report.tplx
	deleted:    latex/style_notebook.tplx
	deleted:    latex/style_simple.tplx
deleted:    latex/latex_article_simple.tplx
Shouldn't have been checked in.
Re-added addprompts() filter (Rebase)
Relative import
Merge pull request #4258 from minrk/backport-1.2

to-backport label is now 1.2
Some small fixes and changes of nb version conversion
Use plain string searching for test exclusions.

Closes gh-4243
Make check for pywin32 more portable.

The attribute is message in Python 2, msg in Python 3.
Merge pull request #4153 from Carreau/timeitobj

make timeit return an object that contains values
Merge pull request #4151 from takluyver/drop-alias

Refactor alias machinery
Keywords should shadow magic functions
Disable autocall for prefilter test
Removing page.less from base style.less.
Merge pull request #4229 from jdfreder/clearoutput

Clear_output: Animation & widget related changes.
Review changes
Merge pull request #4259 from takluyver/win-test-exclusions

Fix Windows test exclusions
Unify exit status from system_raw and system_piped
Add test for exit status from system_piped
Fixing a formatting error in the custom display example notebook.
Merge pull request #4261 from ngoldbaum/master

Fixing a formatting error in the custom display example notebook.