merge: don't overwrite file untracked after remove, abort with 'untracked files'

Merge could overwrite untracked files and cause data loss.

Instead we now handle the 'local side removed file and has untracked file
instead' case as the 'other side added file that local has untracked' case:

  FILE: untracked file exists
  abort: untracked files in working directory differ from files in requested revision

It could perhaps make sense to create .orig files when overwriting, either
instead of aborting or when overwriting anyway because of force ... but for now
we stay consistent with similar cases.
hooks: only disable/re-enable demandimport when it's already enabled

This fixes an issue introduced in d7c28954d901 where, when disabling
demandimport while running hooks, it's inadvertently re-enabled even when
it was never enabled in the first place.

This doesn't affect normal command line usage of Mercurial; it only matters
when Mercurial is run with demandimport intentionally disabled.
help: new SHA-1 fingerprint of hg.intevation.org in hostfingerprints example

The certificate was updated in February 2014.
You can verify the certificate by using the Root CA certificate downloadable
from https://ssl.intevation.de/
The intermediate CA is sent by https://hg.intevation.org/
rebase: do not try to reactivate deleted divergent bookmark

If the currently active bookmark is divergent one, it may be resolved during
rebase.  Trying to activate it will raise "KeyError: 'W@diverge'".
i18n-pt_BR: synchronized with 4e41b2fe46cc
hgweb: make sure sys module is loaded prior to reload hack

If sys is still a demandmod, reload(sys) fails with "TypeError: reload()
argument must be module".
verify: do not prevent verify repository containing hidden changesets

Since a959f7167077, repo.cancopy() cannot be used to check if the repo is
a bundlerepository.

repo.url() should always have "scheme:", so it isn't necessary to parse
by util.url().
pathencode: eliminate signed integer warnings

Compiling mercurial with the Sun Studio compiler gives seven copies of the
following warning on pathencode.c:

    line 533: warning: initializer will be sign-extended: -1

Using explicit unsigned literals silences it.
i18n-ja: synchronized with 7b9d66c0e4fa
merge with i18n