pull: move pulled subset into the object

We compute the set of local changeset that were target of the pull. This is then
used by phases logic to decide which part of the history should have it phase
updated.

We move this information into the object to allow extraction of phase
synchronisation in its own function.

I expect obsolete marker exchange to use it too in the future.
pull: move phases synchronisation in its own function

Now that every necessary information is held in the `pulloperation` object, we
can finally extract the phase synchronisation phase to it's own function.

This changeset is pure code movement only.
pull: make pulled subset a propertycache of the pull object

The computation of the subset is simple operation using two useful pull
information (1) the set of common changeset before the pull (2) the set of
pulled changeset. We move this data into the `pulloperation` object since some
phase will need them. And we turn the pulled subset computation behind a
property case as multiple pull phase will need it.
pull: move `fetch` subset into the object

Tree discovey use a `fetch` variable to know what is being pulled. We move this
information in the `pulloperation` object. This make it possible to extract the
changeset pulling logic into its own function.
pull: move changeset pulling in its own function

pull: move changeset pulling in its own function

Now that every necessary information is held in the `pulloperation` object, we
can finally extract the changeset pulling to it's own function.

This changeset is pure code movement only.
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/

--HG--
branch : stable
merge with stable
merge with crew