XLSX Reader should add a space between text nodes (#229)

When a cell contains multiple text nodes, the cell value is currently obtained by concatenating the value of each text node.
Instead, values should still be concatenated but a space should be added in between.

tests/Spout/Reader/XLSX/Helper/SharedStringsHelperTest.php

@@ -82,6 +82,22 @@ class SharedStringsHelperTest extends \PHPUnit_Framework_TestCase
         $sharedStringsHelper->cleanup();
     }
 
+    /**
+     * @return void
+     */
+    public function testGetStringAtIndexShouldWorkWithStringsContainingTextAndHyperlinkInSameCell()
+    {
+        $resourcePath = $this->getResourcePath('one_sheet_with_shared_strings_containing_text_and_hyperlink_in_same_cell.xlsx');
+        $sharedStringsHelper = new SharedStringsHelper($resourcePath);
+
+        $sharedStringsHelper->extractSharedStrings();
+
+        $sharedString = $sharedStringsHelper->getStringAtIndex(0);
+        $this->assertEquals('go to https://github.com please', $sharedString);
+
+        $sharedStringsHelper->cleanup();
+    }
+
     /**
      * @return void
      */