obshistory: move the command into the obshistory module The root module is far too large already.

obshistory: add docstring to cmddebugobshistory Add debugobshistory command documentation based on the log command documentation.

obshashrangecache: make sure we re-warm the cache after a reset This will "mitigate" the effect of dropping existing entries when new markers affect existing range.

obshashrangecache: precisely track affected revs when adding new markers This will be useful when we start doing finer grained invalidation (instead of dropping all data).

debugobshistory: handle multiple cycles We previously handled up to one cycle only. This is now fixed.

test: clean the debugobshistory cycle test Use 'desc(...)' instead of revision numbers. Also blank lines between commands in the same test

obsdiscovery: add more debug output we add a summary debug output to help gathering data.

discovery: log information about obshashrange We augment the blackbox output to help with data gathering.

obshistory: add a graph option on the debugobshistory command Add a graph option (--graph) to the debugobshistory. The output is like the 'hg log -G' output. The option is activated by default but can be deactivated with '--no-graph' option. There are various issue with the current implementation (multiple cycles handling, N² complexity) but this can be fixed later.

obshistory: import 'node' as 'nodemod' This simplify the next changeset.