Remote API for next/previous service doesn't work

[Tomas Groth]

Tested on Linux with current beta 2.1.1, 2.0 and current trunk.

To reproduce:
Add multiple items to the servicemanager.
Go live with an item
In the web-remote try to use the next/prev buttons, nothing happens. It should shift between service items.

When calling the web API <IP>/api/service/{next,provious} it returns:
{"results": {"success": true}}

The problem might be that we are missing a binding for the servicemanager_{next,provious}_item event.

[Ken Roberts (alisonken1)]

Setup:
- Add song to Service
- Add image to Service
- Add bible verse to image

From android:
- Go to 'Service'
- Click song (Sends song live)
- Click "Next"
Debug shows error trace followed by:
2015-01-06 08:02:08,597 openlp.core.common.registry ERROR Event servicemanager_next_item called but not registered

- Click image
- Click 'Next'
Same error as previous debug error
- Click 'Previous'
Debug shows error trace followed by:
2015-01-06 08:06:17,811 openlp.core.common.registry ERROR Event servicemanager_previous_item called but not registered

[Ken Roberts (alisonken1)]

Webpage has same issue as android

[Ken Roberts (alisonken1)]

Tested using Chrome on Kubuntu, Android app with OpenLP trunk

[Ken Roberts (alisonken1)]

Debug trace for next:

5-01-06 09:08:53,685 openlp.plugins.remotes.lib.httprouter DEBUG Route "^/api/service/(.*)$" matched "/api/service/next?_=1420564133680"
2015-01-06 09:08:53,688 openlp.core.common.registry ERROR OpenLP Error trace
   File /usr/lib/python3.4/threading.py at line 888
         called self._bootstrap_inner()
   File /usr/lib/python3.4/threading.py at line 920
         called self.run()
   File /usr/lib/python3.4/threading.py at line 868
         called self._target(*self._args, **self._kwargs)
   File /usr/lib/python3.4/socketserver.py at line 609
         called self.finish_request(request, client_address)
   File /usr/lib/python3.4/socketserver.py at line 344
         called self.RequestHandlerClass(request, client_address, self)
   File /usr/lib/python3.4/socketserver.py at line 665
         called self.handle()
   File /usr/lib/python3.4/http/server.py at line 398
         called self.handle_one_request()
   File /usr/lib/python3.4/http/server.py at line 386
         called method()
   File /home/ken/projects/openlp/bug-1407445/openlp/plugins/remotes/lib/httpserver.py at line 71
         called self.do_post_processor()
   File /home/ken/projects/openlp/bug-1407445/openlp/plugins/remotes/lib/httprouter.py at line 206
         called self.call_function(function, *args)
   File /home/ken/projects/openlp/bug-1407445/openlp/plugins/remotes/lib/httprouter.py at line 215
         called response = function['function'](*args)
   File /home/ken/projects/openlp/bug-1407445/openlp/plugins/remotes/lib/httprouter.py at line 585
         called Registry().execute(event)
   File /home/ken/projects/openlp/bug-1407445/openlp/core/common/registry.py at line 152
         called trace_error_handler(log)
   File /home/ken/projects/openlp/bug-1407445/openlp/core/common/__init__.py at line 59
         called for tb in traceback.extract_stack():
2015-01-06 09:08:53,688 openlp.core.common.registry ERROR Event servicemanager_next_item called but not registered