add substitutions for dependent variables
add db_table_suffix to allow for shorter table names
minor changes to list of settings that are only in config files ("global_settings")

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@3365 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9