[AtomFormat] improved to comply with RFC 4287

[fulmeek]

This PR improves the Atom format to comply with RFC 4287. It includes unit tests for verification.

[logmanoriginal]

Thanks for the PR!

This is a very complex PR, please split it into multiple pieces:

• Fixing the existing format
• Extending the format
• Adding unit tests

That way reviews are easier to do.

Please also don't align code using tabs. It may work in your editor, but it looks awful in mine (because I use different tab width). The GitHub editor for example is also harder to read like this:

For the core files (anything except bridges), please use curly braces for if-statements:

if($condition === true) {
    // code here
}

[fulmeek]

Thanks for your suggestions, please see the changes.

[fulmeek]

Commit 71b5ed4 should fix issue #1004.

[fulmeek]

Thanks again for your suggestions, please see the changes.

[logmanoriginal]

Thanks, one final thing before I can merge. The alignment tabs need to be removed.

Here is another example from my editor (using a tab width of 4):

Here is tab width of 2 for comparison:

I'm pretty sure it looks fine in your editor, but there is no way to make alignments work for everyone, so we should avoid using them.

[fulmeek]

This should do it.

[logmanoriginal]

Merged. Thanks for the updates!