signalFunctions cannot be imported

[andynoack]

/usr/bin/python-wrapper "/home/ryu/util/Eigene Dateien/Subversion/urh/bin/urh"
Time for generating UI: 1.24 seconds
Using modules from /home/ryu/util/Eigene Dateien/Subversion/urh/src
Traceback (most recent call last):
File "/home/ryu/util/Eigene Dateien/Subversion/urh/bin/urh", line 72, in
os._exit(main(sys.argv)) # sys.exit() is not enough on Windows and will result in crash on exit
File "/home/ryu/util/Eigene Dateien/Subversion/urh/bin/urh", line 32, in main
from urh.controller.MainController import MainController
File "/home/ryu/util/Eigene Dateien/Subversion/urh/src/urh/controller/MainController.py", line 12, in
from urh.controller.CompareFrameController import CompareFrameController
File "/home/ryu/util/Eigene Dateien/Subversion/urh/src/urh/controller/CompareFrameController.py", line 12, in
from urh.controller.OptionsController import OptionsController
File "/home/ryu/util/Eigene Dateien/Subversion/urh/src/urh/controller/OptionsController.py", line 6, in
from urh.controller.PluginController import PluginController
File "/home/ryu/util/Eigene Dateien/Subversion/urh/src/urh/controller/PluginController.py", line 4, in
from urh.models.PluginListModel import PluginListModel
File "/home/ryu/util/Eigene Dateien/Subversion/urh/src/urh/models/PluginListModel.py", line 5, in
from urh.plugins import Plugin
File "/home/ryu/util/Eigene Dateien/Subversion/urh/src/urh/plugins/Plugin.py", line 7, in
from urh.signalprocessing.ProtocolAnalyzer import ProtocolAnalyzer
File "/home/ryu/util/Eigene Dateien/Subversion/urh/src/urh/signalprocessing/ProtocolAnalyzer.py", line 10, in
from urh.cythonext import signalFunctions
ImportError: cannot import name 'signalFunctions'

[jopohl]

Please run src/urh/cythonext/build.py before running from source or install directly with
sudo python setup.py install.

I added these instructions to the Readme file.