Raise minimum Python version to 3.6

scripts/check_dependencies.py

@@ -39,7 +39,7 @@ IS_MAC = sys.platform.startswith('dar')
 
 
 VERS = {
-    'Python': '3.4',
+    'Python': '3.6',
     'PyQt5': '5.0',
     'Qt5': '5.0',
     'sqlalchemy': '0.5',

setup.py

@@ -189,7 +189,7 @@ using a computer and a data projector.""",
     packages=find_packages(exclude=['ez_setup', 'tests*']),
     include_package_data=True,
     zip_safe=False,
-    python_requires='>=3.4',
+    python_requires='>=3.6',
     install_requires=requires,
     extras_require={
         'jenkins': ['python-jenkins'],