Integrate SPL into Phing

[alexeyshockov]

Integrate  SPL features (Iterator, ArrayAccess...) to Phing, as  discussed.

[mp]

A good place to start could be the way FileSets are handled... there is a recurring pattern all over the place that looks like

       	// $fs is a FileSet
    	$fromDir = $fs->getDir($this->project);
       	$ds = $fs->getDirectoryScanner($this->project);
    	foreach ($ds->getIncludedFiles() as $srcFile) {
    	    	$pf = new PhingFile($fromDir, $srcFile)
    	    	...

that could just read

    	foreach ($pf in $fs) {
    	    	...

I don't know whether there is a need at all to access the excludedFile from the directory scanner? When it comes to processing files and directories separately (which I've seen in a few places), PhingFile also supports isFile()/isDirectory().