Fixes in class system. See details.

Fixed class menus not displaying correct class.
Made ClassSelectedNext array for storing class indexes to be set on next spawn. Useful for other stuff too, like saving settings in cookies.
Code cleanup in class spawn and class infect events.

src/zr/playerclasses/filtertools.inc

@@ -295,7 +295,6 @@ stock bool:ClassValidateIndex(classindex)
     }
 }
 
-
 /**
  * Compares the class team ID with a team ID.
  *