Metacat

fixes around getUsers and getGroups.
"getprincipals" action can now produce output like:

<principals>
<group>
<groupname>Administrators<groupname>
<user>
<username>uid=admin,o=NCEAS, c=US<username>
</user>
</group>...

Included back getting the list of users and groups stored in auth scheme
through new action="getprincipals". No extra parameters are needed.
Any logged in users are able to get this information

added precise location information (class.method) to each catch statement so that errors are more easily traced.

Added license terms to source code files, and cleaned up some javadoc
documentation in a few places.

XSLT transformation on "login" and "logout" action

AuthMcat
- new class for authentication through MCA; implements AuthInterface
AuthSession
- assigning HttpSession obj only after successful athentication;
- cleared isAuthenticated field - not needed
- cleared invalidate() method - not needed
AuthInterface...

merge AUTH_LDAP to the main branch