Rename LELA to KIF.Visual

[phatmann]

@bnickel, I would like to rename LELA to KIF.Visual to make it clear that it is part of the KIF ecosystem and what its purpose is. Is this change okay with you?

[bnickel]

What I said here: kif-framework/AMYServer#4

The biggest point against Lela is that it is not really about being functional.

[thefind]

The Zucchini framework supports functional testing via screenshot compares. This has its pros and cons. A visual comparison is a stronger confirmation that everything is working exactly as intended. The downside is that the tests become more fragile and need more frequent updating. For this reason I would like to give KIF users a choice: test success programmatically or visually. LELA provides almost the same toolset as Zucchini and is thus an excellent companion for functional testing.

Since the workflow with LELA is different than with vanilla KIF, I want to maintain it as a separate "plug-in" (at least for now). By renaming it to "KIF.Visual" we can reinforce that this project extends KIF with new functionality and is not a separate, independent component.

I am also hoping that over time other plug-ins will emerge. For example, I am working on a "KIF.Screens" plugin that provides named screens with anchors like Zucchini. By renaming LELA to "KIF.Visual" we can pave the way.

I would take on the task of updating the README, making appropriate code changes, etc.