rts: reader-bin: use fread, skip spaces, and ensure scalar value
rts: reader-bin: use fread, skip spaces, and ensure scalar value

ihc/futhark,ihc/futhark,diku-dk/futhark,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark,HIPERFIT/futhark,ihc/futhark,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark