ja2export is not vendored, we own that + fix errors

stop lying about it by keeping it in ext/
fix three errors in clang-cl

export/src/progress_bar.h

@@ -0,0 +1,23 @@
+#ifndef _PROGRESSBAR_H_
+#define _PROGRESSBAR_H_
+
+#include <vector>
+#include <vfs/Core/vfs_string.h>
+
+namespace ja2xp
+{
+	class ProgressBar
+	{
+	public:
+		ProgressBar(int size, int numElements);
+
+		void Next(vfs::String const& message);
+	private:
+		const int iSIZE;
+		const int num_elements;
+		int count;
+		std::vector<wchar_t> empty_str;
+	};
+};
+
+#endif // _PROGRESSBAR_H_