Massive changes, including:
* Uses a single template specified in the conf file or by GUI.
* Allows setting the font, code font, their sizes and the FG/BG colors
for the WebKit view.
* Make a GObject MarkdownConfig to manage the config and prefs GUI.
* Delete all old templates stuff.
This avoids the caller having to duplicate the internal string and
works for the simple case of the Markdown plugin.
Adds function `mkd_compile_document()` which simply compiles a const
string to a newly-allocated string, hiding the little bit of extra
code needed normally to do this.
There's tons of noise in the commit because I had trailing whitespace
stripping enabled and I re-indented some of the code to make it more
readable (to me).
* Make MarkdownViewer a GObject, and a subclass of WebKitWebView
* A MarkdownViewer "has a" MarkdownConfig property
* Optimize (somewhat) string handling/duplication also using changes
to Discount code.
* Main plugin code manages the scrolled window holding the
MarkdownViewer and monitors the MarkdownViewer's MarkdownConfig
for property changes to know when to move the scrolled window
between the sidebar and message window notebooks.
* Various other cleanups and changes