Estended LDAP integration to allow multiple users search filter.

[mmariuzzo]

This is useful, for example, when your users are inside different organizationUnit and your LDAP server is ActiveDirectory. AD doesn't support complex search query

I've introduced new sections inside config.ini like this one

[Users:ldap:1] ; A free text name for this extra query Alias=italy ; The organization unit where the users are BaseDN=OU=italy,DC=insanefactory,DC=com ; The filter, which identifies the object as a user object. SearchFilter=(&(objectClass=person)(objectClass=user))

[mundtl]

We recently had to install this to work around LDAP performance issues. Works like a charm! <3