Windows fix

[ARajgor]

fix #5

Squash and merge. tested in windows and macos.

1) Fix the window placement issue. now it works on any size of screens. 2) Fix the URL file path for miniwob. there is a bug in urlparse.urljoin()

MINIWOB_DIR = os.path.join(
    os.path.dirname(os.path.realpath(__file__)), "html", "miniwob"
)
MINIWOB_DIR = 'Projects\Synapse\synapse\envs\miniwob\html\miniwob'

subdomain='book-flight'
self.url = urlparse.urljoin(base_url, "{}.html".format(subdomain))
self.url = 'Projects\Synapse\synapse\envs\miniwob\html\book-flight.html'

so the urljoin remove the last miniwob from the base_url. I add '\' to the end.

[ltzheng]

Thanks. LGTM