chgserver: check type passed to S channel It currently only supports the "system" type. Add an explicit check.

chg: send type information via S channel (BC) Previously S channel is only used to send system commands. It will also be used to send pager commands. So add a type parameter. This breaks older chg clients. But chg and hg should always come from a single commit and be packed into a single package. Supporting running inconsistent versions of chg and hg seems to be unnecessarily complicated with little benefit. So just make the change and assume people won't use inconsistent chg with hg.

rebase: fail-fast the pull if working dir is not clean (BC) Refuse to run 'hg pull --rebase' if there are uncommitted changes: so that instead of going ahead with fetching changes and then suddenly aborting the rebase, we can warn user of uncommitted changes (or unclean repo state) right up front. In tests, we create a 'histedit' session to verify that also an unfinished state is detected and handled.

commit: fix unmodified message detection for the "--- >8 ----" magic We need the raw editortext to be compared with the templatetext.