remove dependency on mock

configure.py

@@ -2,8 +2,6 @@ import os
 
 def main():
     os.chdir(os.path.dirname(os.path.realpath(__file__)))
-    # this is needed for mock
-    os.system("pip install --upgrade setuptools")
 
     import get_nwjs
     get_nwjs.main()

setup.py

@@ -41,7 +41,6 @@ INSTALL_REQUIRES = [
     'psutil',
     'ws4py',
     'certifi',
-    'mock',
 ]
 
 EXTRAS_REQUIRES = {