Release of v5.1.1-alpha1

Move all banners to GitHub. Adds library phpspreadsheet to JCB. Adds import item example to demo component. Updates the Superpower class with the GetRemote class in the plugin. Ensures the super power autoloader triggers the correct repositories.

libraries/phpspreadsheet/vendor/maennchen/zipstream-php/guides/ContentLength.rst

@@ -0,0 +1,47 @@
+Adding Content-Length header
+=============
+
+Adding a ``Content-Length`` header for ``ZipStream`` can be achieved by
+using the options ``SIMULATION_STRICT`` or ``SIMULATION_LAX`` in the
+``operationMode`` parameter.
+
+In the ``SIMULATION_STRICT`` mode, ``ZipStream`` will not allow to calculate the
+size based on reading the whole file. ``SIMULATION_LAX`` will read the whole
+file if neccessary.
+
+``SIMULATION_STRICT`` is therefore useful to make sure that the size can be
+calculated efficiently.
+
+.. code-block:: php
+    use ZipStream\OperationMode;
+    use ZipStream\ZipStream;
+
+    $zip = new ZipStream(
+        operationMode: OperationMode::SIMULATE_STRICT, // or SIMULATE_LAX
+        defaultEnableZeroHeader: false,
+        sendHttpHeaders: true,
+        outputStream: $stream,
+    );
+
+    // Normally add files
+    $zip->addFile('sample.txt', 'Sample String Data');
+
+    // Use addFileFromCallback and exactSize if you want to defer opening of
+    // the file resource
+    $zip->addFileFromCallback(
+        'sample.txt',
+        exactSize: 18,
+        callback: function () {
+            return fopen('...');
+        }
+    );
+
+    // Read resulting file size
+    $size = $zip->finish();
+    
+    // Tell it to the browser
+    header('Content-Length: '. $size);
+    
+    // Execute the Simulation and stream the actual zip to the client
+    $zip->executeSimulation();
+