Enable populating user name and email with SAML 1.1 attributes

It's possible to pass arbitrary attributes with the SAML 1.1 ticket.
Attributes are often used to pass the name and e-mail address of the
user to the application. This patch enables to configure which
attributes match the name and e-mail data and populates the user details
with the values found in the corresponding SAML attributes.
Provide user login to user authentication

The previous behaviour accidentally worked because the CAS plugin
provided user login as real name in the user details and Sonar
authentication code sets the login name to match the real name if
login name is missing but details are provided. The proper way
is to provide the login name properly in the first place. This
patch does exactly that.
Oops, fixed the logic in check for a valid assertion
Compatibility with Sonar 3.7.3
Merge remote-tracking branch 'tjormola/populate-user-details-from-saml11-attributes'
Merge remote-tracking branch 'tjormola/provide-user-login-name-when-authenticating'
Merge remote-tracking branch 'jerzykrlk/master'