Ok, in laravel 4, if I want to add my own custom class, eg : library\\myFunction.php then I do the following steps :
This should help you.
FYI: Basically, you could create another directory within app, and then namespace your files in there as appropriate:
app/CustomStuff/CustomDirectory/SomeClass.php.
Then, within your SomeClass.php, make sure you namespace it:
Now, you can access this class using the namespace within your classes:
use App\CustomStuff\CustomDirectory\SomeClass;