Feature/752 Add optional --quiet flag to tilemaker

[oobayly]

See #752

I had issues getting the VS code debugger to correctly (probably related to microsoft/vscode-cpptools#1385. Disabling the large amount of STDOUT ouput generated when running tilemaker in debug solved the issue.

I've added an optional --quiet flag to tilemaker that defaults to false. When set to true:

if (options.quiet) {
  // Suppress anything written to std out
  std::cout.setstate(std::ios_base::failbit);
}

I'm not sure that this is the best/correct way to do this, but it works. I'm happy to take any advice if it should be changed.

[systemed]

Thanks!