allow native safari automation on real devices > 7.1
turns out maybe it was only 6.x that didn't allow us to do this - fix #3331

also, create a mode where if we expect instruments to exit, we don't try to
connect the bootstrap to the command proxy, avoiding error crashes
- fix #3539, fix #3397
truncate atom in log for webkit-rdp
revert premature settings API merge
bring back @jonahss's settings api changes