SVGHMI: In order to allow widget signature and description to coexist in same ysl2 file, introduced widget_class, widget_defs to declare widget codegen templates and gen_index_xhtml to mark templates that are only usefull in gen_index_xhtml.xslt.
#
# Dockerfile for wxPython3.0 running on python2.7
#
FROM python:2.7-stretch
RUN set -xe \
&& apt-get update \
&& apt-get install -y --no-install-recommends python-wxgtk3.0 python-matplotlib \
&& apt-get install -y --no-install-recommends python-xvfbwrapper xvfb \
&& apt-get clean