add unit test for Element::MergeXmlns
add unit test for Element::MergeXmlns

giantchen2012/libkml,PiRSquared17/libkml,msmitherdc/libkml,libkml/libkml,earthoutreach/libkml,flychen50/trunk,pombreda/libkml,flychen50/trunk,msmitherdc/libkml,pombreda/libkml,azzeddine1265/libkml,rashadkm/libkml,msmitherdc/libkml,giantchen2012/libkml,dreamstreat/libkml,libkml/libkml,rashadkm/libkml,pombreda/libkml,flychen50/trunk,rashadkm/libkml,PiRSquared17/libkml,giantchen2012/libkml,Alwnikrotikz/libkml,giantchen2012/libkml,libkml/libkml,earthoutreach/libkml,pombreda/libkml,aaronblanchard/libkml,azzeddine1265/libkml,earthoutreach/libkml,PiRSquared17/libkml,azzeddine1265/libkml,earthoutreach/libkml,sebastic/libkml,msmitherdc/libkml,sebastic/libkml,PiRSquared17/libkml,flychen50/trunk,cboothe/libkml,cboothe/libkml,PiRSquared17/libkml,libkml/libkml,aaronblanchard/libkml,sebastic/libkml,flychen50/trunk,aaronblanchard/libkml,aaronblanchard/libkml,cboothe/libkml,pombreda/libkml,pombreda/libkml,giantchen2012/libkml,azzeddine1265/libkml,libkml/libkml,dreamstreat/libkml,aaronblanchard/libkml,Alwnikrotikz/libkml,dreamstreat/libkml,cboothe/libkml,Alwnikrotikz/libkml,dreamstreat/libkml,msmitherdc/libkml,PiRSquared17/libkml,flychen50/trunk,sebastic/libkml,Alwnikrotikz/libkml,dreamstreat/libkml,earthoutreach/libkml,rashadkm/libkml,rashadkm/libkml,msmitherdc/libkml,dreamstreat/libkml,sebastic/libkml,msmitherdc/libkml,azzeddine1265/libkml,pombreda/libkml,flychen50/trunk,PiRSquared17/libkml,flychen50/trunk,azzeddine1265/libkml,giantchen2012/libkml,aaronblanchard/libkml,cboothe/libkml,Alwnikrotikz/libkml,giantchen2012/libkml,aaronblanchard/libkml,aaronblanchard/libkml,sebastic/libkml,cboothe/libkml,sebastic/libkml,msmitherdc/libkml,azzeddine1265/libkml,pombreda/libkml,cboothe/libkml,sebastic/libkml,dreamstreat/libkml,dreamstreat/libkml,PiRSquared17/libkml,giantchen2012/libkml,azzeddine1265/libkml,cboothe/libkml