the UpdatePlaylist function updates the table `t` that has been passed
to it and fills it with the current playlist. Also I have removed the
addsong function which felt unneccesary and unused.
Before the Update Function needed the currentDirectoryMap ( the
Functionality was not confirmed ) as a parameter but now I have removed
the currentDirectoryMap. Instead I have added totalPath ( going to
rename this to `absolutePath` ) to the FileNode Struct which is added
during the generation of the directory Tree whenever the selected field
is called we can just pass the totalPath.
This function will be useful to update the expanded view whenever user
navigates the file browser. The expanded view is a table which shows the
directory content.
