feat: support log level off

[Aqours]

We can ignore EEXIST 'errors' which does not cause terminal exist, that look like real errors on CI/Linux/macOS platform.

[nicojs]

Maybe we could if we catch and handle the error correctly?

[nicojs]

I think this is the culprit:

node-link-parent-bin/src/cli.ts

Lines 17 to 18 in 44d3439

	console.error('Error Linking packages', err);
	process.exit(1);

[nicojs]

Anyway, released.
https://github.com/nicojs/node-link-parent-bin/blob/master/CHANGELOG.md#102-2019-07-09

[Aqours]

node-link-parent-bin/src/ParentBinLinker.ts

Line 50 in 30bd706

.catch(err => this.log.error(`Could not link bin ${bin} for child ${childPackage}.`, err))))));

I think we should override existed bin file or catch EEXIST error and give a warning to user, because these errors does not affect child packages bin file.