Use the `static` Keyword

Since this class targets PHP 5.3+, you can use late static binding to
call your static methods and create instance. Much better than harcoding
the class name.
Remove a Short Opening Tag

Can't really on `short_open_tag` to be on for all server configurations,
so don't use it.
Merge pull request #1 from chrisguitarguy/use_static_kw

Use `static` Keyword and Late Static Binding