largefiles: don't actually remove largefiles in an addremove dry run

The addlargefiles() method already properly handled dry runs.

--HG--
branch : stable
context: stop setting None for modified or added nodes

Instead use a magic value, so that we can identify modified or added
nodes correctly when using manifest.diff().

Thanks to Martin von Zweigbergk for catching that we have to update
_buildstatus as well. That part eluded my debugging for some time.

--HG--
branch : stable
extra : rebase_source : 849149cca8c222c24460749aab9e4248a99bebc5
manifest: disallow setting the node id of an entry to None

manifest.diff() uses None as a special value to denote the absence of
a file, so setting a file node to None means you then can't trust
manifest.diff().

This should also make future manifest work slightly easier.

--HG--
branch : stable
extra : rebase_source : 857e37b13a1d1536112b2bf0a105be7a5ccd0212
test-casefolding.t: demonstrate a bug with HFS+ ignoring some codepoints

--HG--
branch : stable
extra : rebase_source : b34c28a7fb3fd3a57b32bdb05ea8534ba159d8f4
encoding: add hfsignoreclean to clean out HFS-ignored characters

According to Apple Technote 1150 (unavailable from Apple as far as I
can tell, but archived in several places online), HFS+ ignores sixteen
specific unicode runes when doing path normalization. We need to
handle those cases, so this function lets us efficiently strip the
offending characters from a UTF-8 encoded string (which is the only
way it seems to matter on OS X.)

--HG--
branch : stable
extra : rebase_source : 1d6750c91e3befb73ce1ff5729ca1be1aa9157a4
darwin: omit ignorable codepoints when normcase()ing a file path

This lets us avoid some nasty case collision problems in OS X with
invisible codepoints.

--HG--
branch : stable
extra : rebase_source : ac945313686283c675264529ac0cc47039aad46f
pathauditor: check for codepoints ignored on OS X

--HG--
branch : stable
extra : rebase_source : cb836e00b483460f23ebcc783f803b8a77ddef73
pathauditor: check for Windows shortname aliases

--HG--
branch : stable
extra : rebase_source : 747b404a15fd373dc1406b4031cfc21455c7c749
Added tag 3.2.3 for changeset 6dad422ecc5a

--HG--
branch : stable
Added signature for changeset 6dad422ecc5a

--HG--
branch : stable
merge with stable