Add Text_Highlighter to Composer

- Fixes critical mistake in boot.php regarding set_include_path
- Fixes minor mistake in text.php regarding strpos order of arguments

Note: This change significantly increases Composer running time because
Text_Highlither is a PEAR package. I'm already planning to replace it
with scrivo/highlight.php.

vendor/composer/include_paths.php

@@ -0,0 +1,16 @@
+<?php
+
+// include_paths.php @generated by Composer
+
+$vendorDir = dirname(dirname(__FILE__));
+$baseDir = dirname($vendorDir);
+
+return array(
+    $vendorDir . '/pear-pear.php.net/Console_Getopt',
+    $vendorDir . '/pear-pear.php.net/Archive_Tar',
+    $vendorDir . '/pear-pear.php.net/Structures_Graph',
+    $vendorDir . '/pear-pear.php.net/XML_Util',
+    $vendorDir . '/pear-pear.php.net/XML_Parser',
+    $vendorDir . '/pear-pear.php.net/PEAR',
+    $vendorDir . '/pear-pear.php.net/Text_Highlighter',
+);