patch from Nathanael Huebbe: 0016 use cdfReadVarSliceSP() in cdiStreamReadVarSlice()

src/stream.c

@@ -1608,9 +1608,13 @@ void cdiStreamReadVarSlice(int streamID, int varID, int levelID, int memtype, vo
     case FILETYPE_NC2:
     case FILETYPE_NC4:
     case FILETYPE_NC4C:
-      if ( memtype == MEMTYPE_FLOAT ) Error("cdfReadVarSlice not implemented for memtype float!");
-      cdfReadVarSliceDP(streamptr, varID, levelID, data, nmiss);
-      break;
+      {
+        if ( memtype == MEMTYPE_FLOAT )
+          cdfReadVarSliceSP(streamptr, varID, levelID, data, nmiss);
+        else
+          cdfReadVarSliceDP(streamptr, varID, levelID, data, nmiss);
+        break;
+      }
 #endif
     default:
       {