Don't use redis.lock.
Use redis piplines.
Increased the timeout of the run_check job.
Some more big chunks of improvements.

- Added PNG renderer.
- Fixed check and project pages to show which projects are affected. Fixes issue #17.
- Added about page and simplified header/footer.
- Improved the check again button visually and feature wise (using a form).
- Made cached template loaders prod only.
- Removed spinner. Down with the 00s!