subrepo: svn abort now depends on exit code (issue2833)

fixed issue2833: aborts nows depends on svn exit code

config: ignore include errors for nonexistent files

Make pull -u behave like pull && update Previously, pull would not update if new branch heads were received, whereas pull && update would move to the tipmost branch head. Also change the "crosses branches" abort in merge.update from "crosses branches (merge branches or use --check to force update)" to "crosses branches (merge branches or update --check to force update)" since it can no longer assume the user is running hg update.

requires: note apparent corruption

readrequires: provide easier to understand error message NEW: $ hg id abort: unknown repository format: requires feature 'foo' (upgrade Mercurial)! OLD: $ hg id abort: requirement 'foo' not supported!