stream-clone: make sure the `stream` capability is set when bundling This is important to start narrowing protocol option in the next changesets.

stream-clone: upgrade the error message for bad stream request The new version if more compact and more consistent with the general Mercurial usage.

stream-clone: yield cache entry in `_entries_walk` too The new function now cover the same ground as _v2_walk.

stream-clone: introduce a _entries_walk That function insert itself between the store and `_v2_walk`. It only deals with StoreEntry unlike `_v2_walk` that deal with actual file. A share of the `_v2_walk` logic will be moved in this new `_entry_walk` function. Having this function will help us to implement a new "v3" version of the protocol that will be more entry centric.

store: make `walk` return an entry for obsolescence if requested so Instead of having dedicated code in the streamclone code, we should have the store deal with advertising the data it contains.

store: yield phases before changelog Creating the `changelog.i` file make the repository usable, so dealing with phase earlier seems better.

store: make `walk` return an entry for phase if requested so Instead of having dedicated code in the streamclone code, we should have the store deal with advertising the data it contains.

cli: add a test of `hg debugnodemap --manifest` this is a new option that's not tested yet

cli: fix spelling in `debugnodemap` error messages

cli: make debugnodemap capable of inspecting an arbitrary nodemap This lets us inspect the manifest nodemap and individual directory nodemaps when treemanifest is used.