Update class-option-multicheck.php

I'm using multicheck-posts option in a metabox, and I received this error:
```
Warning: in_array() expects parameter 2 to be array, string given in 
/wp-content/plugins/titan-framework/class-option-multicheck.php on line 30
```
I printed out $savedValue and found out it's a serialized string. So I unserialized it and it's working now.
Did you test multicheck options before?
Even in the demo theme ( http://demo.titanframework.net/wp-admin/post.php?post=2&action=edit ) you can't check any of the checkboxes (when you save the page they become unchecked again). And it's not displaying the error probably because debug mode is off.