[poppler] Exposing hinting setting

[Albert Astals Cid]

Looking at how we handle font hinting, i see:
 - Cairo outputdev disables it always 
 - Splash one does a "weird" case-by-case:
   * If the truetype bytecode interpreter is one -> enable 
                   (although there is a comment saying the interpreter
                    does not use hinting, but bug 9862 seems to say otherwise)
   * else 
        if using antialias -> disable
        else -> enable

So, should we expose hinting setting through a GlobalParams setting that can 
be set from "userspace" via the glib/qt bindings? So that users that like 
hinting can set it to on? Or is freetype hinting so bad having it always off 
is the best?

Comments?

Albert