Less magic numbers, and centralized theme install function. (#103)

* less magic numbers

* part 2: installing themes

* fix simple theme install
that wasnt such a good idea

* fix shuffle count

* fix shuffle theme install

* change padding name

include/loading.h

@@ -29,6 +29,19 @@
 
 #include "common.h"
 
+typedef struct {
+    u8 _padding1[4 + 2 + 2];
+
+    u16 name[0x40];
+    u16 desc[0x80];
+    u16 author[0x40];
+
+    u8 _padding2[0x2000 - 0x200 + 0x30 + 0x8];
+    u16 small_icon[24*24];
+
+    u16 big_icon[48*48];
+} Icon_s;
+
 typedef struct {
     u16 name[0x41];
     u16 desc[0x81];