Remove exceptions and methods in 2.0

* update twitter_endpoints with isListSubscriber and isListMember
instead of having them in twython.py

* app_key and app_secret in place to take over twitter_token and
twitter_secret

* updated methods to have the short hand description show up, should
always be on first line and the description.. not repeating the function

* fixed other method docs and stuff

twython/twitter_endpoints.py

@@ -257,6 +257,10 @@ api_table = {
         'url': '/lists/subscriptions.json',
         'method': 'GET',
     },
+    'isListSubscriber': {
+        'url': '/lists/subscribers/show.json',
+        'method': 'GET',
+    },
     'deleteList': {
         'url': '/lists/destroy.json',
         'method': 'POST',
@@ -273,6 +277,10 @@ api_table = {
         'url': '/lists/statuses.json',
         'method': 'GET'
     },
+    'isListMember': {
+        'url': '/lists/members/show.json',
+        'method': 'GET',
+    },
     'addListMember': {
         'url': '/lists/members/create.json',
         'method': 'POST',