Added support for optional file include titles

[victorjonsson]

Hate to be a downer but I'm having problems with this solution for two reasons:

• It's implicit. The function arlima_file_args is meant to define the arguments that should be used in the file. Saying that one of these arguments will also be used as a file label in the list manager is implicit.
• It only works because of the logic that makes the new solution (the array declaration) backwards compatible. Once we decide not to support the old way of declaring file args this will stop working, or we will have to take it in consideration when removing the old code.

We could merge it simply to support the feature and keep the code until this implementation completely changes in accordance to #63 ... or you could think out a different way to solve this. Maybe look at pages/main.php and apply a filter to the output of the file name...

[aaslun]

It's OK, I clearly missed the bigger picture here. Thanks for the constructive comments, I'll take a look at what can be done through applied filters instead.