[Enhancement] Allow for per-filetype config (or buffer-scoped character variables)

It would be incredibly nice if I could configure table mode to use markdown compatible tables if the filetype is markdown, but use the default style (which I think looks a little nicer) in other circumstances more easily. If the various character config variables were buffer-scoped rather than strictly global then the user could configure that with autocommands or ftplugin/ files.

For Markdown in particular, maybe that could be baked into the plugin.