Add a couple header files, add some mips_to_c of some previously un-decomped functions (#132)

* Add a couple header files

These files contain function prototypes for matches functions, NON_MATCHING functions,
 and functions used by matched functions.

At this point in time those headers may contain prototypes for functions defined in
 unrelated files, but fixing that will have take time

Signed-off-by: Taggerung <tyler.taggerung@gmail.com>

src/code_80005FD0.h

@@ -0,0 +1,15 @@
+#ifndef CODE_80005FD0_H
+#define CODE_80005FD0_H
+
+#include "common_structs.h"
+
+/* Function Prototypes */
+
+s16 func_80005FD0();
+
+// math_util.c
+u32 func_802B5224();
+
+/* This is where I'd put my static data, if I had any */
+
+#endif