v1.15.0

• Improve error handling and add to manual https://github.com/aaronriekenberg/rust-parallel/wiki/Manual#error-handling
  • Log errors for commands and at end of main log number of failing commands.
  • If at least one command fails rust-parallel exits with status 1
• Add option --exit-on-error to specify rust-parallel exits with status 1 immediately when first command failure is seen.
• Update dependencies with cargo update