debugobsolete: also report the number of obsoleted changesets This seems useful to have the number of obsoleted changesets when calling debugobsolete.

transaction-summary: display the summary for all transactions Now that we records "all" changes happening in a transaction (in tr.changes) we will be able to provide better report on various changes (phases turned public, changeset obsoleted, branch merged or created, etc..) This is far too late in the cycle to play with this, but having this existing method called more widely will help extensions to play around with various options during the 4.4 cycle. Instead of calling registersummarycallback only for transactions we want, we always call it and use the transaction name to decide when to report (eg: we do not want `hg amend` to report new obsoleted changesets). Filtering on transaction name does not seems great, but seems good enough for the moment. We can change the API during the next cycle. The previous manual call during unbundling of the bundle2 "obsmarkers" part is no longer necessary and has been dropped.

test-strip: fix call to super class in crashstriprepo The 'self' argument is already taken care of by the 'super(...)' call. Instead we were passing the repository instance as the 'desc' value. This got discovered by breaking the next changeset.

share: share 'cachevfs' with the source clone (issue5108) Share extension now also share caches reads and writes. Not sharing caches results in costly caches recomputations which can takes up to minutes when using shares on large repositories. There are a couple of file in the '.hg/cache/' that depends of the current visibility. Visibility can be affected by the working copy location, something which is specific to each share. We ignores them for this series because they: * are the minority, * already have a good fallback to other precomputed caches, * are only affected when people use the experimental evolution feature.

cachevfs: add a devel warning for cache access though 'vfs' This will help third party extensions to migrate to the new 'cachevfs'.

cachevfs: migration the tags fnode cache to 'cachevfs' This will help sharing the cache between shares.

cachevfs: migrate tagscache to 'cachevfs' This will help sharing the cache between shares.

cachevfs: migration the revbranchcache to 'cachevfs' This will help sharing the cache between shares.

cachevfs: use the new vfs in when computing branchmap cache This will help sharing the cache between shares.

cachevfs: add a vfs dedicated to cache Most of the cache content lives in '.hg/cache/'. Moreover they are computed exclusively from data in the '.hg/store' directory. This creates issues with the share extension as the '.hg/store' directory is shared but the '.hg/cache' is not. On large repositories, this makes this prevent some usage of the share extension inefficient as some caches can take minutes to be recomputed. To improve the situation, we introduce a new 'cachevfs' that will be dedicated to cache reading and writing. In the next patches of this series, we'll migrate the 4 existing caches to it and update the share extension.