run-tests: print a newline after all warnings

annotate: fix alignment of columns in front of line numbers (issue2807)

merge with stable

revset: the name is optional for the tag predicate

revset: note case-sensitive match in grep

revset: note case-insensitive matches in keyword and user

revset: expand help for contains predicate

patch: remove unused variable to make pyflakes test happy

patch: add lexists() to backends, use it in selectfile() At this point, all applydiff() filesystem calls should pass through fsbackend.

patch: move copyfile() into backends, abstract basedir

patch: merge makerejlines() into write_rej()

patch: extract fs access from patchfile into fsbackend Most filesystem calls are already isolated in patchfile but this is not enough: renames are performed before patchfile is available and some chmod calls are even done outside of the applydiff call. Once all these calls are extracted into a backend class, we can provide cleaner APIs to write to a working directory context directly into the repository.