[IMP] auth_crypt: auto-install, improve description, bump version

The compatibility issue with auth_ldap has been
fixed and the default key derivation function
switched to PKDF2+SHA512. `auth_signup` provides
a password reset mechanism that can be used in
combination with `auth_crypt`.
Merge branch '8.0' of https://github.com/odoo/odoo into 8.0-linux64