2012-05-01 Made removal of invisible nodes operate in a case-insensitive manner... Thanks Juha P.! 2012-02-07 Fixed some recent code introductions to use class constants rather than global constants. Fixed some recent code introductions to make it cleaner to read. 2012-01-31 Fixed a bug that was introduced with the 2011-12-22 revision... Thanks Sagi L. and M. BÄ…kowski! Added extraction of