graft: use merge.graft

merge: add merge.graft helper This will help unify all the open-coded graft/rebase operations.

duplicatecopies: move from cmdutil to copies This is in preparation for moving its primary caller into merge.py, which would be a layering violation in the current location.

histedit: fix indent The duplicatecopies call should be part of the rebase block.

graft: move rebase cleanup code next to actual rebase This is prep for refactoring the rebase logic.

shelve: add a bundlerepo method

dirstate: merge falls through to otherparent This lets us more correctly fix the state when we use setparents, as demonstrated in the change in test-graft.t.

dirstate: use 'm' state in otherparent to reduce ambiguity In rebase-like operations where we abandon the second parent, we can correctly fix up the state in setparents.

dirstate: properly clean-up some more merge state on setparents

phases: move root phase assignment to it's own function This moves the initial root phase assignment to it's own function. Future patches which make phase calculations lazy will use this function to pre-fill certain phases which can be deduced from the roots.