graphlog: split the actual DAG grapher out into a separate method
This allows extensions like pbranch to use asciigraph() to graph dependencies
for patch branches, but could be used for basically any DAG.
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
0 files, 0 changesets, 0 total revisions
00changelog.i
requires
store
updating working directory
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
0 files, 0 changesets, 0 total revisions
00changelog.i
branch
dirstate
hgrc
requires
store