Merge pull request #472 from PyBossa/generalise-presenters

add copyright boilerplate
Updated translations
Fix the broken lazy_gettext error
PEP-8
Update translations.
fix name of template arg
move importer variant enumeration out of main importer function
make importer classes yield task data; have importer do the adding
remove extraneous references to app from internals of importers
remove use of app in importers
change error message explicitly referenced from test code(!?)
Merge pull request #475 from PyBossa/generalise-importers6

Generalise importers - tidy up class interface
Regexp validator for not allowing / char in app.short_names
New validator for non-allowed chars. Closes #474
Add the back slash as a forbidden char.
Add the validator to the username forms.
PEP-8 compliant
Refactor the validators to their own module. Refs #474
Update unit tests for validators.
Fix Flask-Mail hack to make pass unit test.

This commit fixes the TODO item in the test_web.py file that had
a typo in the config variable MAIL_DEFAULT_SENDER (it was written DEFAULT_MAIL_SENDER).