ODS writer

Added ODS writer
Refactored XLSX writer to abstract some pieces into an abstract multi-sheets writer
Created an abstract style helper
Moved shared components around

src/Spout/Reader/XLSX/Helper/SharedStringsHelper.php

@@ -79,6 +79,7 @@ class SharedStringsHelper
     {
         $xmlReader = new XMLReader();
         $sharedStringIndex = 0;
+        /** @noinspection PhpUnnecessaryFullyQualifiedNameInspection */
         $escaper = new \Box\Spout\Common\Escaper\XLSX();
 
         $sharedStringsFilePath = $this->getSharedStringsFilePath();
@@ -90,9 +91,7 @@ class SharedStringsHelper
             $sharedStringsUniqueCount = $this->getSharedStringsUniqueCount($xmlReader);
             $this->cachingStrategy = $this->getBestSharedStringsCachingStrategy($sharedStringsUniqueCount);
 
-            while ($xmlReader->read() && $xmlReader->name !== 'si') {
-                // do nothing until a 'si' tag is reached
-            }
+            $xmlReader->readUntilNodeFound('si');
 
             while ($xmlReader->name === 'si') {
                 $node = $this->getSimpleXmlElementNodeFromXMLReader($xmlReader);

src/Spout/Reader/XLSX/Helper/SheetHelper.php

@@ -126,6 +126,7 @@ class SheetHelper
                 $sheetId = (int) $sheetNode->getAttribute('sheetId');
                 $escapedSheetName = $sheetNode->getAttribute('name');
 
+                /** @noinspection PhpUnnecessaryFullyQualifiedNameInspection */
                 $escaper = new \Box\Spout\Common\Escaper\XLSX();
                 $sheetName = $escaper->unescape($escapedSheetName);
             }

src/Spout/Reader/XLSX/RowIterator.php

@@ -77,6 +77,7 @@ class RowIterator implements IteratorInterface
         $this->sharedStringsHelper = $sharedStringsHelper;
 
         $this->xmlReader = new XMLReader();
+        /** @noinspection PhpUnnecessaryFullyQualifiedNameInspection */
         $this->escaper = new \Box\Spout\Common\Escaper\XLSX();
     }