SpiffyTitles: migrate templates to Jinja2

[butterscotchstallion]

Replacing the templates used now with Jinja would allow logic in templates, which could solve the following use case:

Example template: ^ You know what time it is? :: $type $widthx$height $file_size :: $view_count views :: $nsfw

• User wants to show $title only if it's available
• Since only simple variable replacement is all that's available, this is not possible and the user is left with a blank space when the title is unavailable

Jinja2 example:

^ {% if title %}{{title}} :: {% endif %} image/jpeg 500x667 63.3KiB :: {{views}} views :: {% if nsfw is null %}not sure if nsfw{% endif %}{%if nsfw is True %}not safe for work{% endif %}{%if nsfw is False %}safe for work{% endif %}