Deprecate w-id/w-for attributes

[mlrawlings]

The w-id attribute was used to obtain references using this.getEl(refId). w-id has been replaced with the ref attribute.

Renaming these attributes for clarity and because we want to remove references to marko-widgets.

w-id → ref
w-for → for-ref

I like this because it's more clear that this for-ref will create for that points to the id generated by ref

Old:

<input type="text" w-id="name" />

New:

<input type="text" ref="name" />

Similarly, w-for has been been replaced with for-ref:

Old:

<label w-for="name">Name</label>
<input type="text" w-id="name" />

New:

<label for-ref="name">Name</label>
<input type="text" ref="name" />

[ctdio]

If no one has started working on this, I can take this one up.

[patrick-steele-idem]

@charlieduong94 That would be great if you could take this issue. I invited you as a collaborator so that I can assign this issue to you. You can click the following link to accept: https://github.com/marko-js/marko/invitations

Thanks!

[ctdio]

PR #427

[patrick-steele-idem]

Work completed. Closing issue. Thanks @charlieduong94 !