filelog: add file function to open other filelogs

help: add -c/--command flag to only show command help (issue2799)

help: give hint about 'hg help -e' when appropriate The hint is only given if a command shadows an extension with the same name and when that extension has a multi-line module docstring.

help: add -e/--extension switch to display extension help text

debugbuilddag: read DAG from stdin if not given on cmdline

run-tests: remove check on --shell argument No shell is needed when executing Python tests and finding a good shell might be difficult/impossible on some platforms (e.g., Windows).

subrepo: create subrepos using clone instead of pull Subrepositories used to be created empty and then filled with data using pull. This is wasteful when you do a clone from a local source since it means that no hardlinks are created for the subrepos. This patch make the hgsubrepo._get method check for an empty subrepo and in that case do a clone instead of a pull. This brings in the same data as before, but creates hardlinks when possible.

progress: add speed format This is not enabled by default, but the user can add it by setting progress.format. We might want to let the estimate format output a speed instead of an ETA if there is not total. Currently estimate just returns the empty string in that case.

debugbuilddag: output progress information

test-debugbuilddag: replace unneeded 'rm -rf' with 'rm -r'