readFromFile/readFromBlob result returning also the QR code coordinates inside the source image

[pedrospinto]

Proposed changes

...as discussed in https://github.com/chillerlan/php-qrcode/issues/240

Types of changes

What types of changes does your code introduce?

• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [x] I have checked to ensure there aren't other open Issues or Pull Requests for the same update/change
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added necessary documentation (if appropriate)
• [ ] Any dependent changes have been merged and published in downstream modules
• [ ] Lint and unit tests pass locally with my changes

[codemasher]

Hey! Thank you for the PR! I'm going to add some thoughts to the files - no worries, I don't bite :)

2 things kept me thinking:

• What's the best way to test it? (maybe take one or more of the samples in /tests, determine & verify the results and hardcode them?)
• How does the ZXing app (from which the decoder is ported) do it? The app displays the centers of the detected finde- and alignment patterns while scanning, so there has to be code that does exactly what this PR is supposed to do.