supress chmod and touch warnings

On some file systems these commands will fail. It's unclear what systems
those are, I can reproduce it for touch() on my android phone (but not
on my tablet).

Instead of littering the output with potentially thousands of warnings
we supress them here. Ideally we should probably do something with them,
but I don't know what.

Maybe a strict setting that turns them into exceptions, would work? PRs
welcome.

Author: splitbrain

src/Tar.php

@@ -184,8 +184,8 @@ public function extract($outdir, $strip = '', $exclude = '', $include = '')
                 }
 
                 fclose($fp);
-                touch($output, $fileinfo->getMtime());
-                chmod($output, $fileinfo->getMode());
+                @touch($output, $fileinfo->getMtime());
+                @chmod($output, $fileinfo->getMode());
             } else {
                 $this->skipbytes(ceil($header['size'] / 512) * 512); // the size is usually 0 for directories
             }

src/Zip.php

@@ -232,7 +232,7 @@ public function extract($outdir, $strip = '', $exclude = '', $include = '')
                 unlink($extractto); // remove temporary gz file
             }
 
-            touch($output, $fileinfo->getMtime());
+            @touch($output, $fileinfo->getMtime());
             //FIXME what about permissions?
             if(is_callable($this->callback)) {
                 call_user_func($this->callback, $fileinfo);