Replace hardcoded python version with ARG variable The Dockerfile had a hardcoded Python version in install paths and COPY command in the second stage build. Replace that with a hardcoded ARG pythonversion. Add RUN command to verify pythonversion against the actual version installed in the docker image. If they do not match generate an appropriate --build-arg for the docker build command that will match the docker image version. Document the use of the variable and why it's needed in installation.txt. Also fix typos referencing --build-args and bad values for the arguments.

@import url(style.css);

body { padding: 0;}
body > .header,
body > .footer
{
  margin: 0;
}
body .content { width: auto;}
.header h1 { font-size: 110%; }

table.classhelp th
{
  border-top: 1px solid #afafaf;
  border-bottom: 1px solid #afafaf;
  empty-cells: show;
  text-align: left;
  vertical-align: middle;
  white-space: nowrap;
}

table.classhelp td
{
  border-bottom: 1px solid #efefef;
  empty-cells: show;
  text-align: left;
  vertical-align: middle;
  white-space: nowrap;
}