model: Use Series instead of PatchSet

The git documentation uses the term series diffusely and the main
users of the software prefer it over "patch set".
mailparse: Add fake series for non-git-format-patch
model: Add a tag property for Project
model: Update relationships
template: Drop unused javascript include
views: Make it modular

Move everything in Blueprints when possible
mailparse: Update the patch state
project: Show the stale patches