[DOC beta] Remove JSDoc @scope directives.

`@scope` is not valid `YUIDoc` syntax (see [syntax reference](http://yui.github.io/yuidoc/syntax/index.html)), and causes last properly documented method/property in a file to contain the text output of any undocumented items directly following the `@scope` directive.


Before:

![screenshot](https://www.monosnap.com/image/pZCrf3m2vdqlROOUCjIuJre4a.png)

After:

![screenshot](https://www.monosnap.com/image/rfCxDtISxjm19SM85RZKbbPgK.png)


Before:
![screenshot](https://www.monosnap.com/image/ZDxRuuf9vyxMBVqIZUlghxrID.png)

After:

![screenshot](https://www.monosnap.com/image/J9eCBqdHonuB8UXC0eWQ6gQuf.png)