Code Standards: Finish up admin includes

* fixed indentation - swapped spaces for tabs at start of line, swapped
tabs for spaces min-line for alignment
* removed instances of `@return void` and `@access public`

@see http://make.wordpress.org/core/handbook/coding-standards/php/

@see part 1: #6157
Merge pull request #6876 from tamarazuk/coding-standards-part-2

Code Standards Part 2