allow to login with email instead of nick as well + tests
start of making nickname optional
fix typo breaking invitation
make search work without nickname usage
more user display changes
user display changes in model and mailer
small model change
make user creation possible again
show user name with use_nick is false
beautify map invocations of users
fallback for when nick is nil
fix new user form
Merge branch 'master' into allow-no-nickname

Conflicts:
	app/views/foodcoop/users/_users.html.haml
clearer login field name
make authentication methods more readable (thanks @fsmanuel)
use dynamic conditional in validation, to enable different foodcoops having different use_nick configuration values
Merge branch 'master' into allow-no-nickname

Conflicts:
	app/views/home/ordergroup.html.haml
	app/views/login/new_password.html.haml
	app/views/shared/_auto_complete_users.rhtml
	app/views/shared/memberships/_current_members.rhtml
	app/views/shared/memberships/_non_members.rhtml
Merge pull request #189 from foodcoops/allow-no-nickname

Make the use of a username optional