topics: add t0 and b0 to the stack
t0 or b0 will be the base of the stack and it's the parent of t1 or b1. The cool
thing about this is that if you update to t0 using `hg up t0` or do `hg prev` on
t1, you will be updated to t0 with the current topic preserved.
This patch adds t0 to stack and implement the preserving topic case for t0 while
using `hg update`.
#require test-repo
$ checkcm() {
> if ! (which check-manifest > /dev/null); then
> echo skipped: missing tool: check-manifest;
> exit 80;
> fi;
> };
$ checkcm
$ cat << EOF >> $HGRCPATH
> [experimental]
> evolution=all
> EOF
Run check manifest:
$ cd $TESTDIR/..
$ check-manifest
lists of files in version control and sdist match