Register qversion as a non repository related command

Show remote ssh noise only with --debug and increase the limit to 500 lines. Messages can already be sent to the user over stderr, if one really wants this.

document the possible race in "hg undo"

Don't allow --style and --template for hg update and hg merge. The only way that changesets will be shown with these command is in an error message when trying to update to an ambiguous branch name.