Print assoc group more pretty
Print assoc group more pretty

svn path=/trunk/StrategoXT/; revision=3457

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