Don't expose rate, mixdown, dither and encoder arrays to the UIs.

Don't expose rate, mixdown, dither and encoder arrays to the UIs.

- instead, make these lists available through enumerators:
--> hb_*_get_next(<type> *last);

- this should give us more flexibility to populate the lists at runtime, using the implementation(s) of our choice, whether they use arrays or not, without requiring UI modifications

- use consistent naming for getters
--> hb_get_best_foo() becomes hb_foo_get_best(), and so on

- hb_*_get_from_name() and hb_*_ sanitize_name() sanitize the requested value to a supported one if it's unavailable

- adds an additional, passthru-specific fallback mechanism

- adds a list of video containers

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5526 b64f7644-9d1e-0410-96f1-a4d463321fa5