fixes .rtree files as inputs
fixes .rtree files as inputs

svn path=/trunk/StrategoXT/; revision=9293

Apanatshka/strategoxt,lichtemo/strategoxt,metaborg/strategoxt,Apanatshka/strategoxt,metaborg/strategoxt,metaborg/strategoxt,Apanatshka/strategoxt,Apanatshka/strategoxt,metaborg/strategoxt,lichtemo/strategoxt,lichtemo/strategoxt,metaborg/strategoxt,lichtemo/strategoxt,Apanatshka/strategoxt,lichtemo/strategoxt