stack: also change the indexing of the t# reference Changeset 61f36480740f changed the index displayed (we now index from 1), but forgot to update the logic used to resolve the 't#' name. This changeset fixes it.

stack: change the ascii symbold for base Now that the children line go upward, '_' is no longer clear as is take the lower part of the line. We go for '^' that use the upper part.

stack: reverse the display order Most mercurial command display the most recent changeset first. We put `hg topic --list` inline with this.