Add ability to specify ldap search scope for grouperClient

New pull request was created at https://github.com/Internet2/grouper/pull/61 . This is added functionality to the grouperClient whereby the ldap search scope can be specified in the grouper.client.properties file.
e.g:
ldapSearchAttribute.searchScope.0 = sub
ldapSearchAttribute.searchScope.1 = one
This is an optional parameter. It can be set to 'one', 'sub', or 'base' for one level, subtree, or base ldap search respectively. If not specified or set to blank, the search scope defaults to 'one' for backwards compatibility.