Needed for chromium 55

- Update to 2.8
- Added `target` parameter to urlize function.
- Added support for `followsymlinks` to the file system loader.
- The truncate filter now counts the length.
- Added equalto filter that helps with select filters.
- Changed cache keys to use absolute file names if available
instead of load names.
- Fixed loop length calculation for some iterators.
- Changed how Jinja2 enforces strings to be native strings in
Python 2 to work when people break their default encoding.
- Added :func:`make_logging_undefined` which returns an undefined
object that logs failures into a logger.
- If unmarshalling of cached data fails the template will be
reloaded now.
- Implemented a block ``set`` tag.
- Default cache size was incrased to 400 from a low 50.
- Fixed ``is number`` test to accept long integers in all Python versions.
- Changed ``is number`` to accept Decimal as a number.
- Added a check for default arguments followed by non-default arguments. This
change makes ``{% macro m(x, y=1, z) %}...{% endmacro %}`` a syntax error. The
previous behavior for this code was broken anyway (resulting in the default
value being applied to `y`).
- Add ability to use custom subclasses of ``jinja2.compiler.CodeGenerator`` and
``jinja2.runtime.Context`` by adding two new attributes to the environment
(`code_generator_class` and `context_class`) (pull request ``#404``).
- added support for context/environment/evalctx decorator functions on
the finalize callback of the environment.
- escape query strings for urlencode properly. Previously slashes were not
escaped in that place.
- Add 'base' parameter to 'int' filter.