TEST(phpt): add Italic and Underline test file

tests/008.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Check for vtiful presence
+--SKIPIF--
+<?php if (!extension_loaded("excel_writer")) print "skip"; ?>
+--FILE--
+<?php 
+$config = ['path' => './tests'];
+$excel = new \Vtiful\Kernel\Excel($config);
+$handle = $excel->fileName('tutorial01.xlsx')
+    ->getHandle();
+$italicStyle = \Vtiful\Kernel\Format::italic($handle);
+var_dump($italicStyle);
+?>
+--EXPECT--
+resource(5) of type (vtiful)

tests/009.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Check for vtiful presence
+--SKIPIF--
+<?php if (!extension_loaded("excel_writer")) print "skip"; ?>
+--FILE--
+<?php 
+$config = ['path' => './tests'];
+$excel = new \Vtiful\Kernel\Excel($config);
+$handle = $excel->fileName('tutorial01.xlsx')
+    ->getHandle();
+$underlineStyle = \Vtiful\Kernel\Format::underline($handle, \Vtiful\Kernel\Format::UNDERLINE_SINGLE);
+var_dump($underlineStyle);
+?>
+--EXPECT--
+resource(5) of type (vtiful)