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/ui.h

@@ -0,0 +1,15 @@
+#pragma once
+
+struct rgbColor
+{
+	char rC;
+	char gC;
+	char bC;
+};
+
+typedef struct rgbColor Color;
+
+Color makeColor(char r, char g, char b);
+s8 drawPixel(u32 x, u32 y, Color c, u8* screen);
+s8 drawLine(u32 x1, u32 y1, u32 x2, u32 y2, Color c, u8* screen);
+s8 drawRect(u32 x1, u32 y1, u32 x2, u32 y2, Color c, u8* screen);