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/Basic1/13_CalculationCyclicFormulae.php

@@ -0,0 +1,36 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../Header.php';
+
+// Create new Spreadsheet object
+$helper->log('Create new Spreadsheet object');
+$spreadsheet = new Spreadsheet();
+
+// Add some data, we will use some formulas here
+$helper->log('Add some data and formulas');
+$spreadsheet->getActiveSheet()->setCellValue('A1', '=B1')
+    ->setCellValue('A2', '=B2+1')
+    ->setCellValue('B1', '=A1+1')
+    ->setCellValue('B2', '=A2');
+
+Calculation::getInstance($spreadsheet)->cyclicFormulaCount = 15;
+
+// Calculated data
+$helper->log('Calculated data');
+for ($row = 1; $row <= 2; ++$row) {
+    for ($col = 'A'; $col != 'C'; ++$col) {
+        $formula = $spreadsheet->getActiveSheet()->getCell($col . $row)->getValue();
+        if (
+            is_string($formula)
+                && ($formula[0] == '=')
+        ) {
+            $helper->log('Value of ' . $col . $row . ' [' . $formula . ']: ' . $spreadsheet->getActiveSheet()->getCell($col . $row)->getCalculatedValue());
+        }
+    }
+}
+
+// Save
+$helper->write($spreadsheet, __FILE__);