Fix checksum generation.

The algorithm used for checksum generation is not explicitly specified
in the .goo format spec and was implemented wrong until now. The printer
ignores the checksum so this wasn't a problem. This implementation is
now equivalent to the one used in UVTools.

Author: Felix-Rm

src/libslic3r/SLA/RasterBase.cpp

@@ -226,7 +226,7 @@ EncodedRaster GOORLERasterEncoder::operator()(
 
     // Write checksum
     uint8_t checksum =
-        std::reduce(output_buffer.begin() + 5, output_buffer.end(), 0, std::bit_xor<uint8_t>{});
+        ~std::reduce(output_buffer.begin() + 5, output_buffer.end(), 0, std::plus<uint8_t>{});
     output_buffer.push_back(checksum);
 
     // Write delimiter

src/libslic3r/SLAPrintSteps.cpp

@@ -1145,8 +1145,6 @@ void SLAPrint::Steps::merge_slices_and_eval_stats() {
                 else
                     fast_layers++;
 
-                BOOST_LOG_TRIVIAL(error) << sliced_layer_cnt << ' ' << total_layer_time;
-
                 layers_times.push_back(total_layer_time);
                 estim_time += total_layer_time;
             }