Introduce class name changes in new namespace

[mikey179]

This introduces the class name changes proposed with #213 into the v1.x series according to the migration strategy detailed in #221.

In case you are wondering about duplication of TestCase classes - I doubled some of them, keeping the old version targeted at the org\bovigo\vfs namespace, and for the renamed classes I introduced the same TestCase classes using the renamed classes. This should help to ensure that everything is compatible in the way we expect it to be.

[mikey179]

I tested vfs-stream-examples and some of my project against this, and both an update without any namespace and class name adoptions in the project and adopting the new namespace with the new class names went without any problems. Maybe if you have some projects depending on vfsStream you could do the same to ensure we really deliver a seamless upgrade experience. Just because it went fine in my projects doesn't mean it will in others.

[allejo]

A simple "replace all" was enough for me to get all of my usage upgraded.

[jaapio]

I surely want to do this, but think I don't have time to do it this month. So feel free to merge this PR and I will report any issues.

Maybe we can come up with some phprector script to help people upgrade?