thread-pool v1.3

• Version 1.3 (2021-05-03)
  • Fixed this issue: Removed std::move from the return statement in push_task(). This previously generated a -Wpessimizing-move warning in Clang. The assembly code generated by the compiler seems to be the same before and after this change, presumably because the compiler eliminates the std::move automatically, but this change gets rid of the Clang warning.
  • Fixed this issue: Removed a debugging message printed to std::cout, which was left in the code by mistake.
  • Fixed this issue: parallelize_loop() no longer sends references for the variables start and stop when calling push_task(), which may lead to undefined behavior.
  • A companion paper is now published at arXiv:2105.00613, including additional information such as performance tests on systems with up to 80 hardware threads. The README.md has been updated, and it is now roughly identical in content to the paper.