merge: don't report progress for dr/rd actions It is easier to reason about certain algorithms in terms of a file->action mapping than the current action->list-of-files. Bid merge is already written this way (but with a list of actions per file), and largefiles' overridecalculateupdates() will also benefit. However, that requires us to have at most one action per file. That requirement is currently violated by 'dr' (divergent rename) and 'rd' (rename and delete) actions, which can exist for the same file as some other action. These actions are only used for displaying warnings to the user; they don't change anything in the working copy or the dirstate. In this way, they are similar to the 'k' (keep) action. However, they are even less action-like than 'k' is: 'k' at least describes what to do with the file ("do nothing"), while 'dr' and 'rd' or only annotations for files for which there may exist other, "real" actions. As a first step towards separating these acitons out, stop including them in the progress output, just like we already exclude the 'k' action.

subrepo: add partial diff support for git subrepos So far, git subrepositories were silently ignored for diffs. This patch adds support for git subrepositories, with the remark that --include and --exclude are not supported. If --include or --exclude are used, the subrepo is ignored.

subrepo: extend git version check to 3 digits This allows more flexibility when a version check is required. Some git features are introduced in a version where only the 3rd digit changes.