Merge pull request #251 from darkhouse/feature/issue26

Fixed issue #26. Added max_filename_increment as a config setting.
diff --git a/system/libraries/Cache/drivers/Cache_memcached.php b/system/libraries/Cache/drivers/Cache_memcached.php
index ae9d6cd..04aa81a 100644
--- a/system/libraries/Cache/drivers/Cache_memcached.php
+++ b/system/libraries/Cache/drivers/Cache_memcached.php
@@ -64,7 +64,7 @@
 	 */
 	public function save($id, $data, $ttl = 60)
 	{
-		return $this->_memcached->add($id, array($data, time(), $ttl), $ttl);
+		return $this->_memcached->set($id, array($data, time(), $ttl), $ttl);
 	}
 
 	// ------------------------------------------------------------------------
diff --git a/system/libraries/Email.php b/system/libraries/Email.php
index e28c23a..28a3d17 100644
--- a/system/libraries/Email.php
+++ b/system/libraries/Email.php
@@ -452,7 +452,7 @@
 	 */
 	public function set_alt_message($str = '')
 	{
-		$this->alt_message = $str;
+		$this->alt_message = (string) $str;
 		return $this;
 	}
 
@@ -477,12 +477,12 @@
 	 * Set Wordwrap
 	 *
 	 * @access	public
-	 * @param	string
+	 * @param	bool
 	 * @return	void
 	 */
 	public function set_wordwrap($wordwrap = TRUE)
 	{
-		$this->wordwrap = ($wordwrap === FALSE) ? FALSE : TRUE;
+		$this->wordwrap = (bool) $wordwrap;
 		return $this;
 	}