Add community edition message
Update COMMUNITYEDITION.md
Update COMMUNITYEDITION.md
Update COMMUNITYEDITION.md
More helpful information about Google and Facebook
show an error message when user can't authenticate by `authenticate_user_login()` call
show an instrutive error message when user can't authenticate via `authenticate_user_login()` call
show an instrutive error message when user can't authenticate via `authenticate_user_login()` call
possible cause is email registered by another auth plugin
correct urls to login page and forgot password
correct urls to login page and forgot password (cast to string)
Check that a failed authentication is due to an email already in use
Some Spanish strings added

Conflicts:
	lib.php
Language strings
Finished translating lang file
Small correction in the translation
Fix the providers count logic
Use parameter in the sign-in string - kudo to hdomos for the origin string fix #66
User creation fails if the user prefix is in uppercase and moodle has usernames in lowercase
Hide buttons when auth method is disabled
Do not show the login button if one of the Google settings (app key or secret) are empty