Implemented the "ref" namespace to get configuration tree references. BUGS: - Tests should be done more thoroughly and extensively - Interaction of tree references and variable substitution should be tested more properly - Documentation is missing yet

[config]
tmpdir = {{_tmpdir}}\2

[config.db.user]
name = the_database_user_2
__doc2 = Overwriting a comment
pwd=the-database-password-2

[config.db.locinfo.ro]
hostname = 3rd-host