Fixes #135 - Convert Makefile to xcodeproject. Demo in its own folder now with its own Makefile.

demo/demo.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int main(int argc, const char* argv[]) {
+    int i;
+    for (i = 0; i < argc; i++) {
+        printf("argv[%d] = %s\n", i, argv[i]);
+    }
+    return 0;
+}