add wget and unzip dependencies for building on Windows

These are needed to fetch ASIO SDK and nw.js binaries

README.md

@@ -105,7 +105,8 @@ pacman -S autoconf automake git libtool \
           mingw-w64-i686-ftgl mingw-w64-i686-fribidi \
           mingw-w64-i686-ladspa-sdk mingw-w64-i686-lame \
           mingw-w64-i686-libsndfile mingw-w64-i686-libvorbis \
-          mingw-w64-i686-lua mingw-w64-i686-toolchain</code>
+          mingw-w64-i686-lua mingw-w64-i686-toolchain \
+          unzip wget</code>
 4. Type `exit` in the shell and click the `Enter` key  
    This will close the window.
 5. Open the MinGW-w64 Win32 Shell again, as you did in *step 2* above.