replaced sbarpic_t with cachepic_t in sbar code (saves a bit of memory)

replaced sbarpic_t with cachepic_t in sbar code (saves a bit of memory)
changed DrawQ_SuperPic and DrawQ_Pic to take a cachepic_t * instead of a pic name (this speeds up the sbar code by not using name lookups constantly)
removed DrawQ_Fill (use DrawQ_Pic with NULL pic instead)
changed crosshair/editlights cursors to use r_crosshairs array initialized at startup instead of constantly calling Draw_CachePic
changed Host_Init to call SCR_BeginLoadingPlaque instead of Host_StartVideo (which is called by SCR_BeginLoadingPlaque)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@6058 d7cf8633-e32d-0410-b094-e92efae38249