minui: Export minui/minui.h.

For libminui static and shared libraries.

Test: build
Change-Id: Ib30dc5e2ef4a3c8b3ca3a0cec68cb65e229a0c16
diff --git a/minui/resources.cpp b/minui/resources.cpp
index 9ccbf4b..e6909f2 100644
--- a/minui/resources.cpp
+++ b/minui/resources.cpp
@@ -31,7 +31,7 @@
 #include <vector>
 #include <png.h>
 
-#include "minui.h"
+#include "minui/minui.h"
 
 #define SURFACE_DATA_ALIGNMENT 8