Update Jinja2 (Python template library) to 2.7.1

Jinja2 (used in Blink scripts in Source/core and Source/bindings) has
been updated to 2.7.1 (from existing 2.6); see changelog.

The specific new features in this release that are useful are:
* keep_trailing_newline
* lstrip_blocks
...which make it easier to control whitespace, making templates easier to read.
(Specifically it lets us easily indent control blocks.)
* selectattr (allows filtering lists in template, simplifying Python code)

In the Changelog these are referred to as:
Added support for keeping the trailing newline in templates.
Added finer grained support for stripping whitespace on the left side of blocks.
Added map, select, reject, selectattr and rejectattr filters.

BTW, 2.7 is the first Jinja2 major release in 2 years;
2.7.1 is a bugfix release:
2.7   2013-05-20
2.7.1 2013-08-07

This upgrade introduces a new dependency (on Windows), due to the safe string class being factored out into a separate library.
Thus depends on separate CL:
Add MarkupSafe library to third_party (dependency for Jinja2 2.7)
This has been committed as r221578:


Review URL: https://chromiumcodereview.appspot.com/23506004

Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: e6e0570955d4fdf7f3e077124ce520b397680ff9
29 files changed