Runtime: work around 1s delay added when using twisted reactor's callLater.

Since wxPython4, using wxReactor from non-main thread was producing
exceptions in wxWidget's C++ code. Then reactor.run() was called from
main thread, and runtime's worker was delegating calls to reactor
with callLater(0, callable).

While this worked perfectly with wxReactor, it did introduce an unexplained
1 second delay to each worker call when using nomal linux reactors
(i.e. without wxPython). As a workaround reactor runs in a thread when using
twisted without wxPython

# those files are used in runtime
# licensed according to LGPL, see COPYING.runtime 

images/icostop24.png
images/icoplay24.png
images/brz.png
util/__init__.py
util/paths.py
runtime/WampClient.py
runtime/PLCObject.py
runtime/NevowServer.py
runtime/webinterface.js
runtime/webinterface.css
runtime/__init__.py
runtime/ServicePublisher.py
runtime/typemapping.py 
runtime/loglevels.py 
Beremiz_service.py
version.py