Initial commit
Switch to python3
Allow generating thumbnails of a given width or height.
Preliminary support for tags and better layout.

Tags are stored in an sqlite database. Let's keep things easy.
Always use url_for()
Factor the database handling in a separate module.
Add proto tool to add images and tags.
Use argparse for dumbgald
Allow adding tags from the web interface.
Only display tags with at least one tagged image.
Display the amount of images in each tag page.