* Set appropriate file stat times

Since we are creating the destination file, it's our responsibility to set the file stat times.

* fix code style

The modularized lodash packages are unmaintained since 2 years, lagging a lot
behind the main lodash package. Partial imports of lodash are the preferred
way.

This documents the option to use Dart Sass, and encourages users to
explicitly choose their implementation, but it doesn't change the
existing behavior.

Rather than always loading Node Sass, this now requires users to pass
in either Dart Sass or Node Sass to the require() call.

Closes #672

It's not clearly documented how to add options to sass.sync, and this is implemented inconsistently across other code infrastructures, so it's not safe to assume whether it's `sass(options).sync()` or `sass.sync(options)` please accept the pull request if the proposed documentation is correct, or otherwise accept it anyways and provide a follow up merge as an update fix.

Declaring logError as function instead of arrow function.

Drop support for non-Active LTS and Current releases

Closes dlmanning/gulp-sass#646

Closes #649

Make the latest stable node-sass the minimum.

Fixes #588

Force update to LibSass 3.5.0.

Closes #620