Adding code base to support .jshintignore for JSHint linter.

[orlandoibm]

Honour .jshintignore when that file exists in the project being validated.

This is highly based on the work originally discussed and advanced here: https://github.com/angelozerr/tern.java/issues/265

I noticed that under some scenarios, a few tweaks are necessary to inform JSHint about the correct ignore paths, so most of the work is about handling those special cases (extensive code documentation).

[angelozerr]

@orlandoibm it seems that it's a cool feature!

But is it possible to do a PR for https://github.com/angelozerr/tern-jshint project and add a test please with your new feature. Thanks!

[orlandoibm]

Hi @angelozerr. I am sorry I did not have time to move my fix to the other repo. I saw you already implemented it, so hopefully this helped you somehow.

Regards :) Orlando