bugfix: feed only uc ACGU to RNAcontext to avoid segfaults & warn on N or other undefined characters
bugfix: feed only uc ACGU to RNAcontext to avoid segfaults & warn on N or other undefined characters

dmaticzka/GraphProt,dmaticzka/GraphProt,dmaticzka/GraphProt,dmaticzka/GraphProt,dmaticzka/GraphProt