Translation of UI (german and english)

Bugfix for feeds
    - removed categories related and up
    - load new books now working
    - category random now working
login page is free of non accessible elements
boolean custom column is vivible in UI
books with only with certain languages can be shown
book shelfs can be deleted from UI
Anonymous user view is more resticted
Added browse of series in sidebar
Dependencys in vendor folder are updated to newer versions (licencs files are now present)
Bugfix editing Authors names
Made upload on windows working

vendor/requests/hooks.py

@@ -10,36 +10,25 @@ Available hooks:
 
 ``response``:
     The response generated from a Request.
-
 """
-
-
 HOOKS = ['response']
 
 
 def default_hooks():
-    hooks = {}
-    for event in HOOKS:
-        hooks[event] = []
-    return hooks
+    return dict((event, []) for event in HOOKS)
 
 # TODO: response is the only one
 
 
 def dispatch_hook(key, hooks, hook_data, **kwargs):
     """Dispatches a hook dictionary on a given piece of data."""
-
     hooks = hooks or dict()
-
-    if key in hooks:
-        hooks = hooks.get(key)
-
+    hooks = hooks.get(key)
+    if hooks:
         if hasattr(hooks, '__call__'):
             hooks = [hooks]
-
         for hook in hooks:
             _hook_data = hook(hook_data, **kwargs)
             if _hook_data is not None:
                 hook_data = _hook_data
-
     return hook_data