SA-master todos

[sshane]

Todo list for https://github.com/sshane/openpilot/tree/SA-master

• [ ] Allow comments in files_release
• [ ] Build release branch?
• [x] Model MPC for e2e button?
• [x] Do UI
• [x] Remove custom longitudinal delay code, use the one in stock!
• [x] Ensure dirty stays stock, but create sa_dirty or similar for personal Sentry
• [x] Clean up added controlsd code
• [x] Clean up changes around openpilot now in stock
• [ ] Revert longcontrol and PID to stock and rethink/retune
• [x] Make sure camera_offset is correct for C3
• [x] Fix version in title bar