- backend: add summoner spells
- backend: add build variants
- backend: builds are now storing full tree with runes (keystones)
- backend: build trees are split on starter items and merged on runes
- frontend: computing core tree now
- frontend: variant selectors
- Remove items/runes separate pages, put everything into a "build" page.
- Show summoner spells.
- Add a build variant selector, that for now only selects runes