Makes libzip asynchronous by mimicing the uv_fs_* APIs.

Usage

See test/test.cpp

Testing

$ ./configure
[...]
$ make test
[...]
* open_failure (0.9ms)
* open_from_fd (0.9ms)
* missing_file (0.2ms)
* read_file (0.2ms)

Note: This binding is not complete and only provides read-only support.