0.53.3

From CHANGELOG.md:

Fixed

• invader-build: Fix defaulting model filthy part indices.

Changed

• invader-build: bitmap sequence index is now checked in more places.
• invader-build: particle system tags are now checked to make sure an extra
  bitmap sequence is available after the one referenced when using the "rotational"
  complex sprite render mode.
• invader-edit-qt: grenade_hud_interface field naming has been made clearer.