Adding default service_urls list issue#165

[terryyz]

https://github.com/ssut/py-googletrans/issues/165

[coveralls]

Coverage increased (+2.7%) to 92.222% when pulling f0ce952 on terryzhuo110:issue_165 into afb17c7 on ssut:master.

[coveralls]

Coverage decreased (-0.08%) to 89.453% when pulling cfee004 on terryyz:issue_165 into afb17c7 on ssut:master.

[ssut]

Could you describe purpose of this? I think it would be a good idea to put this in constants if you just wanted to show possible service urls.

[terryyz]

Yes, this is for showing available service urls we can use. User can choose one of them they like. I've put the list in the constant. Do you mean it would be better if I set def __init__(self, service_urls=None, user_agent=DEFAULT_USER_AGENT, proxies=None, timeout=None): proxies=None, timeout=None, available_service_list=DEFAULT_SERVICE_URLS) ?

[ssut]

@terryyz It seems self.available_service_list is not referenced from the Client's methods so I think it does not need to have that property (available_service_list) in Client, storing in constants is enough.

[terryyz]

Okay. I will close this and pull another request.