[Fluxus] obj loading speed

[gabor papp]

hi Dave,

> In that case, a quick fix might be to save out the primitives from
> fluxus, as they should be quicker to load back in once processed this
> way.
unfortunately that didn't work, because the conversion algorithm still 
had to process all indices.

i optimized the loading a bit by merging the vector loading and storing 
the unified index per face vertex. on a 1 megabyte obj file, the loading 
time dropped from 5.6 seconds to 2.1, which is still too slow.

best,
gabor