Fix handling of paths when run outside the repo. The main problem was that dirstate.getcwd() returned just "", which was interpreted as "we're at the repo root". It now returns an absolute path. The util.pathto function was also changed to deal with the "cwd is an absolute path" case.

abort: repository a not found!
255
abort: error: Connection refused
255
abort: repository a not found!
255
abort: destination '../a' already exists
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abort: repository a not found!
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destination directory: q
abort: destination 'q' already exists