optimizations + bugfixes

* Bombs explode on damage/explosion
* Orbits spell fixed
* Performance: implemented shared component indexes,
compiled Lua caching, and updates only for changed projectile fields.
Also removed accumulating hidden entity slots.

shaders/proj_step.comp

@@ -59,6 +59,7 @@ int shot_flags(int typeFlags, int dz) { return ((dz >> 10) & 1) != 0 ? (typeFlag
 bool victim_at(vec2 pos, int shooter, int herd, int flags, int age, out int hit) {
     hit = -1;
     for (int k = 0; k < ctrl.inp.w; ++k) {
+        if (ents[k].ex19.w == -float(gl_GlobalInvocationID.x + 1u)) continue; // its own damage proxy
         const int kind = ents[k].st.x;
         if (kind == 0 && (ents[k].st.w & 64) != 0 && ents[k].ex19.w > 0.5) {   // a worm's segment (WormComponent hitbox_radius around every part): the hit goes to the worm
             const int root = int(ents[k].ex19.w) - 1;