Log Message:
Update to 2.6.4:

2.6.4
----------

- Improve assertion failure reporting on iterables, by using ndiff and pprint.

- removed outdated japanese docs from source tree.

- docs for "pytest_addhooks" hook.  Thanks Bruno Oliveira.

- updated plugin index docs.  Thanks Bruno Oliveira.

- fix issue557: with "-k" we only allow the old style "-" \ 
for negation
  at the beginning of strings and even that is deprecated.  Use "not" \ 
instead.
  This should allow to pick parametrized tests where "-" appeared in \ 
the parameter.

- fix issue604: Escape % character in the assertion message.

- fix issue620: add explanation in the --genscript target about what
  the binary blob means. Thanks Dinu Gherman.

- fix issue614: fixed pastebin support.