PHP Command Line Parser: Invoke functions to process command-line arguments

This package can invoke functions to process command-line arguments.

It can take as a parameter the $argv array passed to PHP as the array of command line arguments and an array that defines options on how to process those arguments.

The package can process the arguments by invoking a callback function that applications pass to process the command line argument values.

It can also call a given callback function to process when all arguments are processed and when no arguments are passed to the package.