Universalmediaserver: Make all settings positive

[SubJunk]

I think it would be good to go through the user settings and change instances of negatives to positives, for example "Do not add engine names to filenames" would become "Add engine names to filenames", etc.
The old settings should be kept with a deprecated flag for backwards-compatibility.
I think this will make our settings easier to understand more quickly.

[Sami32]

@SubJunk I agree with it, not that it bother me, but i can remember psychological studies on that subject.
http://www.psychologicalscience.org/index.php/news/releases/true-or-false-how-our-brain-processes-negative-statements.html

EDIT: But add again more settings since we have already to much deprecated class to clean that was already kept for compatibility reason many years ago...i'm not sure that is a so good idea after all ?
How many percent of UMS users really read the configuration files ?

[SubJunk]

I did some of this in 7.0.0 already BTW

[SubJunk]

I think this is done