fix unnecessary lambda and enable corresponding pylint check

fix wrong-import-order. first standard modules are imported, then others

fix (old-style-class) Old-style class defined error for most parts of
the code

only PyJS code is left, because it does some fancy tricks and can't be
easily fixed. So far PyJS doesn't support Python3 anyway.

remove in-tree version of Zeroconf and use upstream from
python-zeroconf package

remove reimported modules

fix unnecessary parens after keyword

enable pylint checker

so far only print statement is checked

fix usage of python2-only print statement

run python tests with non-english locale to catch bugs related to localization

make it possible to update XSD schema in project controller after new
target PLC is added or removed.

For example:


...
import targets
targets.targets["PLC"] = {"xsd": os.path.join(self.customBeremizPath, "PLCtarget", xsd),
"class": lambda: PLC_target,
"code": {"plc_PLC_main.c": os.path.join(self.customBeremizPath, "PLCtarget", "plc_PLC_main.c")}
}

from ProjectController import ProjectController, GetProjectControllerXSD
ProjectController.XSD = GetProjectControllerXSD()

fix commit "lazy initialization of highlight pens and brushes
for DebugVariableViewer" (5562f34f)

clean build example project after running test

fix problem if DataTypeEditor was imported before localization is
loaded

That doesn't affect systems with english locales.

add shell script to run all python tests and automatically handle Xvfb

add PLCOpenEditor tests