Renaming test dir to playground.
Adding anonymous examples from php.net
Added a todo with online sources.
Added examples of variable functions as a preface to anonymous functions.
Added more examples of anonymous functions, including nested anonymous functions.
Documented anonymous functions.
Add closure examples.
Add example of filtering numbers with using closures.
Added a dump of information about a closure object using the reflection api.
Added an example demonstrating the availability of variables accessed within a closure.
Fixed spelling error.
Updating todo doc.
Added an example of a method that expects a callback as a parameter.
Merge pull request #14 from aczietlow/php-oop

Php oop