Updated EmailField error message. This one already available in django translations.

https://github.com/django/django/blob/master/django/conf/locale/ru/LC_MESSAGES/django.po#L343
Fixed test
added script block to list of blocks

Phew, was afraid I wouldn't be able to overwrite this section..
Merge pull request #996 from speg/patch-1

added script block to list of blocks
Merge pull request #995 from pzinovkin/patch-1

Updated EmailField error message.
Add @pzinovkin for #995 thanks!
Merge remote-tracking branch 'upstream/master' into writable-nested-modelserializer