SVGHMI: add support for multiline widget declaration using svg:desc.
Declaration started in inkscape:label and interupted by a '\' can be continued in the description field.
After an empty line, the rest of the description field is left for description text.
# opcua/__init__.py
from __future__ import absolute_import
from .client import OPCUAClient
# class RootClass(object):
# XSD = """<?xml version="1.0" encoding="ISO-8859-1" ?>
# <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
# </xsd:schema>
# """
# CTNChildrenTypes = [("OPCUAClient", OPCUAClient, "OPCUA Client")]
#