This is a initial fix to permit user to change the file association
preferences again.

Change the settings url to be mor consistant with the others urls of the
app.

Better feedback if the saving of settings did work or not.

Use the Framework to get the settings value, instead of using the $_POST
array.

The Settings controller parameters were did not have a type, and
prevented them from being automatically injected

Remove the 'personal.php' file to remove the duplicate personal settings
page

It seems personal.js is used in the settings too, so i changed the URL
there too.