player collection order

[Yoni Rabkin]

As per:

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=57630

...and this:

http://git.savannah.gnu.org/cgit/emms.git/commit/?id=e9fa4c095d007e16365348cb0a1b42e37ed8e701

...you can see that the order in which players which can play a given
track are collected has been reversed.

If you happen to have code which relied on the previous order, please
take note.

However, the preferences system in emms.el, via the function
`emms-players-preference-f', is the preferred way to prefer a specific
player for a specific track or type of track.

-- 
   "Cut your own wood and it will warm you twice"