Allow typo in search key

* Introduce Levenshtein algorithm
* New API param 'typos' to give number of typos allowed
* test cases

Change-Id: I22bf34d08a910d1509d7eab5adc292eadc9a7c7d

tests/phpunit/LanguageSearchTest.php

@@ -54,6 +54,14 @@ class LanguageSearchTest extends PHPUnit_Framework_TestCase {
 				'fro' => 'الفرنسية القديمة',
 				)
 			),
+			array( "മലയളം", array(
+				'ml' => "മലയാളം",
+				)
+			),
+			array( "finish", array(
+				'fi' => 'finnish'
+				)
+			),
 		);
 	}
 }