Reorganize Samples

The samples have become unwieldy when running them from a browser. In particular, the drop-down lists are fixed size with no scrolling, and many of them are now just too large. I have moved all the Calculation samples up a level, and broken several categories (Basic, Chart, DateTime, Engineering, Financial, and Reader) into several pieces.

Convert-Online (now found in the Engineering category) had a number of different problems which are now resolved. It is the only member with any significant code change.

samples/Basic3/37_Page_layout_view.php

@@ -0,0 +1,32 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\SheetView;
+
+require __DIR__ . '/../Header.php';
+
+// Create new Spreadsheet object
+$helper->log('Create new Spreadsheet object');
+$spreadsheet = new Spreadsheet();
+
+// Set document properties
+$helper->log('Set document properties');
+$spreadsheet->getProperties()->setCreator('PHPOffice')
+    ->setLastModifiedBy('PHPOffice')
+    ->setTitle('PhpSpreadsheet Test Document')
+    ->setSubject('PhpSpreadsheet Test Document')
+    ->setDescription('Test document for PhpSpreadsheet, generated using PHP classes.')
+    ->setKeywords('Office PhpSpreadsheet php')
+    ->setCategory('Test result file');
+
+// Add some data
+$helper->log('Add some data');
+$spreadsheet->setActiveSheetIndex(0)
+    ->setCellValue('A1', 'Hello')
+    ->setCellValue('B2', 'world!');
+
+// Set the page layout view as page layout
+$spreadsheet->getActiveSheet()->getSheetView()->setView(SheetView::SHEETVIEW_PAGE_LAYOUT);
+
+// Save
+$helper->write($spreadsheet, __FILE__);