Add src/windows that contains necessary files to produce native JNI
library for Windows.

Signed-off-by: Haochen Xie <haochen@xie.name>
Modifications to JarLibraryLoader and Platform to allow Windows native
library being loaded.

Signed-off-by: Haochen Xie <haochen@xie.name>
Adding prebuilt Windows native libraries (x86 and x64).

Signed-off-by: Haochen Xie <haochen@xie.name>
Add a jjs runnable JavaScript test script to ease testing whether native
library is loaded on a specific platform.

Signed-off-by: Haochen Xie <haochen@xie.name>