localrepo: remove clone method by hoisting into hg.py
hg.py was the only remaining caller of localrepo.clone(), so it's time
to move some more behavior out of localrepo.
filemerge: default regular prompts to 'leave unresolved' (BC)
It makes far more sense to leave these conflicts unresolved and kick back to
the user than to just assume that the local version be chosen. There are almost
certainly buggy scripts and applications using Mercurial in the wild that do
merges or rebases non-interactively, and then assume that if the operation
succeeded there's nothing the user needs to pay attention to.