fix #84 check if the filename is String. filename could be Tempfile, for instance.
fix #84 check if the filename is String. filename could be Tempfile, for instance.

xchanging-mm4/roo,fabien-michel/roo,RobertRehberg/roo,airblade/roo,malept/roo,pricematch/roo-legacy,stevendaniels/roo,pricematch/roo-legacy,visagio/roo,myplaceonline/roo,salsify/roo,enemycnt/roo,maruware/roo,culturecode/roo,pabloh/roo,thotmx/roo,roo-rb/roo,pricematch/roo-legacy,reshleman/roo