Cookie Test

# Tests
include 5 test base on previous selenium java test implementation, [link](https://code.google.com/p/selenium/source/browse/java/client/test/org/openqa/selenium/CookieTest.java)
 
* test_can_create_a_well_formed_cookie
* test_cookies_should_allow_secure_to_be_set
* test_secure_defaults_to_false
* test_should_throw_an_exception_when_semicolon_exists_in_the_cookie_attribute( __bug__ )
* test_should_throw_an_exception_the_name_is_null( __bug__ )

# Reference
* [Cookie RFC2019] (http://www.ietf.org/rfc/rfc2109.txt)
* [W3C WebDriver spec] (https://dvcs.w3.org/hg/webdriver/raw-file/tip/webdriver-spec.html#cookies)
* [W3C WebDriver test README] (http://www.w3.org/wiki/WebDriver/Test_suite)
* [Python selenium web driver implement doc] (http://selenium-python.readthedocs.org/en/latest/api.html?highlight=cookie#module-selenium.common.exceptions)
* [Python unittest doc] (http://docs.python.org/2/library/unittest.html)