Initial basic functionality commit

What this commit adds:
* Ability to apply a theme, given a folder
* Extract all .zip files in /Themes/ into a relevant folder
* Get all theme metadata from info.smdh
* Proper unicode handling

What's still needed for initial release:
* Theme shuffling
* GUI

source/theme.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "minizip/unzip.h"
+#include "linked_lists.h"
+
+struct theme_data
+{
+	u16 title[0x40];
+	u16 description[0x80];
+	u16 author[0x40];
+	char iconData[0x1200];
+	u16 path[533];
+	bool bgm;
+};
+
+typedef struct theme_data theme_data;
+
+u8 regionCode;
+u32 archive1;
+u32 archive2;
+
+FS_Archive ArchiveSD;
+FS_Archive ArchiveHomeExt;
+FS_Archive ArchiveThemeExt;
+
+Result unzip_theme(FS_DirectoryEntry*, u16*);
+Result prepareThemes(node*);
+Result themeInstall(theme_data);
+Result closeThemeArchives();
+Result parseSmdh(theme_data*, u16*);