[sparticle] 2d hud particles (#849)

* wip, taking a break to work on asm stuff first

* the goal code for sparticle

* mips2c the first sparticle asm function

* temp

* particle processing no longer crashing

* temp

* working texture cache for vi1 and hud textures

* sprites

* cleanup 1

* temp

* temp

* add zstd library

* temp

* working

* tests

* include fix

* uncomment

* better decomp of sparticle stuff, part 1

* update references

game/kernel/kmachine.cpp

@@ -748,6 +748,13 @@ void vif_interrupt_callback() {
   }
 }
 
+/*!
+ * Added in PC port.
+ */
+u32 offset_of_s7() {
+  return s7.offset;
+}
+
 /*!
  * Final initialization of the system after the kernel is loaded.
  * This is called from InitHeapAndSymbol at the very end.