oll-doc: Add snippet code version
oll-doc: rename field names

It seems necessary to have *all* fields prefixed with "snippet-".
This is to avoid ambiguities.

Additionally this commit stores the determined \version string
as a field "snippet-version" in the headerFields dictionary.
oll-doc: Tiny line breaking improvement
oll-doc: Make HTML generation object oriented

The initial approach was extremely hacky, now we have proper HTML
objects making use of the template pattern and inheritance.
oll-doc: Allow saving to HTML files

HtmlFile.save()
Snippet.saveToHtml()
Snippets.saveToHtml()
MainWindow.saveSnippetsToHtml()

write out the content of one or all snippets to corresponding files
in the /doc folder.

Currently there is no user interface for this, but I've tested that
it works correctly. To be useful this needs an alternative HTML output
for the HtmlFile class because then the navigation has to be done
*in* the page and not outside of it in the application.
oll-doc: Reflect html.py renaming in Eric project
oll-doc: Initial output of navigation in html file

For file output we need the navigation in the file itself.
This commit provides a two-column layout with the left column
containing the navigation structure.
Completely un-styled so far.
oll-doc: diversify CSS files

Have two independent CSS files to be used for in-app and
in-browser viewing, and include other stuff from there.

This is very sketchy so far.
oll-doc: Generate HTML page title
oll-doc: re-read current snippet on lib reread

When the library is reread the current snippet is displayed
again (if the name is still there). So any external changes to
the snippet will be reflected in the GUI.
oll-doc: Create navigation content by using templates

This is of course significantly better than the initial sketch
Merge branch 'doc-script' into reorganization
oll-doc: Add Frescobaldi's CSS
oll-doc: Add syntax highlighting to code output

If python-ly is installed on the machine we can use it to
generate HTML output with syntax highlighting!
oll-doc: Update Eric4 TODO file