Include standard webpack start/end locations in emitted errors

[lorenzodallavecchia]

This PR adds the loc property to all errors coming from TypeScript diagnostics.
The property is the webpack "API" way of indicating the precise location of an error, including its end location.
In this way, the errors produced by ts-loader can be processed from the webpack Stats object, with no knowledge of ts-loader.

The previous location property is still available, so the change is backward-compatible.

Webpack will print its own error location string in the string output, in addition to the line and character that ts-loader already includes in the error message. All comparison tests are updated to expect the new output.

Closes #1199

[johnnyreilly]

This looks good - thanks for contributing!

Could you update the package.json and the CHANGELOG.md please? I'll do another review later, but I think this is probably good to ship.

[lorenzodallavecchia]

Could you update the package.json and the CHANGELOG.md please?

Done!

[johnnyreilly]

Keep getting a failing test.. rerunning

[lorenzodallavecchia]

@johnnyreilly yeash, I was thinking it was a known problem with the Travis setup.
By looking at the details it seems that the comparison tests on Ubuntu are being aborted after 15 minutes. Maybe they are taking too much time? On Windows the complete after 20 minutes.

[johnnyreilly]

Passing now - go figure

[johnnyreilly]

https://github.com/TypeStrong/ts-loader/releases/tag/v8.0.17 - released!

Thanks for contributing 🌻❤️