slow smooth scrolling drawing performance

[argarak]

many references to threads blocked by the DC queue (draw call?). needs to be optimised as currently the PSP port performs better in melee (inexcusable). changing from SDL thread to pthread library made no difference, maybe use native threads? will need to investigate

[argarak]

after today's play testing i found that the main source of the lag in melee is due to the smooth 3DO scrolling option. setting it to the classic stepped option seems to be work well so maybe there's a way of fixing the transitions in some manner. otherwise i might disable it or set it as a default option (i like the stepped zoom anyways, but that's just my preference)

[argarak]

megamod on android provides multiple interpolation options for melee zoom, may be a round about way of fixing it if all else fails