Port to node.js v0.10

There is an API signature change in v0.10 that causes OpenCC to fail to install with an error:

>   CXX(target) Release/obj.target/binding/node/binding.o
../node/binding.cc:71:5: error: no matching function for call to 'uv_queue_work'
    uv_queue_work(uv_default_loop(), req, DoConnect, AfterConvert);
    ^~~~~~~~~~~~~
/Users/lalau/.node-gyp/0.10.0/deps/uv/include/uv.h:1397:15: note: candidate function not viable: no known conversion from 'void (uv_work_t *)' to 'uv_after_work_cb' (aka 'void (*)(uv_work_t *, int)') for
      4th argument
UV_EXTERN int uv_queue_work(uv_loop_t* loop, uv_work_t* req,
              ^
1 error generated.
make: *** [Release/obj.target/binding/node/binding.o] Error 1

API signature change in v0.10:
https://github.com/joyent/node/wiki/Api-changes-between-v0.8-and-v0.10
https://github.com/rbranson/node-ffi/commit/fdeff41ae8b1cca31d4707d7b61253c45181b8fa