Fix login url and update test cassettes (#99)

+ Login URL on geocaching.com changed from `account/login` to
`account/signin`
+ Update all betamax cassettes regarding login transactions
+ Fixes issue #98

Author: weinshec

pycaching/geocaching.py

@@ -25,7 +25,7 @@ class Geocaching(object):
 
     _baseurl = "https://www.geocaching.com"
     _urls = {
-        "login_page":        "account/login",
+        "login_page":        "account/signin",
         "search":            "play/search",
         "search_more":       "play/search/more-results",
     }