Support for in-html css and js

[bartvaneswhiffle]

Currently, a HtmlLog creates a stylesheet and javascript, which makes sharing a report a bit inconvenient. The HTMLHEAD in _html.py can be slightly modified to support the use of text based stylessheets and javascripts. Therefore I would like to propose this feature request.

[gertjanvanzwieten]

It's a good suggestion, thanks. We'll keep this issue open until a next version allows for some form of user customization of the html output.