Fix broken ryfs_read routine, bump version to 0.3.1

There were two issues here:
First, ryfs_read_sector_loop was not setting the current sector to the
next sector of the file being read. This had the effect of making it
read the same sector over and over again.
Second, the destination pointer for the `copy_memory_bytes` call wasn't
being changed after each sector copy.

main.asm

@@ -4,7 +4,7 @@
 
 const FOX32ROM_VERSION_MAJOR: 0
 const FOX32ROM_VERSION_MINOR: 3
-const FOX32ROM_VERSION_PATCH: 0
+const FOX32ROM_VERSION_PATCH: 1
 
 const SYSTEM_STACK:     0x01FFF800
 const BACKGROUND_COLOR: 0xFF674764

ryfs.asm

@@ -199,7 +199,14 @@ ryfs_read_sector_loop:
     pop r1
     pop r0
 
-    dec r10
+    ; this_sector = this_sector.next
+    mov r5, TEMP_SECTOR_BUF
+    add r5, 2
+    movz.16 r5, [r5]
+    mov r4, r5
+
+    add r2, r11
+    sub r10, r11
     ifnz jmp ryfs_read_sector_loop
 
     ; file_struct.file_seek_offset += input r0