move Z2Calc, c_math and f_op_draw_iter (#125)

* Z2Calc

* port over c_math

* fop_draw_iter

Co-authored-by: Pheenoh <pheenoh@gmail.com>

libs/SSystem/SComponent/c_bg_w.cpp

@@ -23,8 +23,7 @@ void cBgW_BgId::Release() {
 
 /* 802681D4-802681E4 262B14 0010+00 0/0 7/7 121/121 .text            ChkUsed__9cBgW_BgIdCFv */
 unsigned int cBgW_BgId::ChkUsed() const {
-    unsigned int temp = mId - 0x100;
-    return temp >> 0x1f;
+    return mId < 0x100;
 }
 
 /* 802681E4-802681FC 262B24 0018+00 1/1 22/22 8/8 .text            cBgW_CheckBGround__Ff */

libs/SSystem/SComponent/c_m3d_g_cir.cpp

@@ -7,12 +7,6 @@
 #include "dol2asm.h"
 #include "dolphin/types.h"
 
-//
-// External References:
-//
-
-void operator delete(void*);
-
 //
 // Declarations:
 //