Ftw.upgrade

-------------------

- Fix error in upgrade-step:directory directive.
The error occured when the directory was a subdirectory relative to the
ZCML directory, causing the package module to be replaced with the
upgrades package directory in sys.modules.
[jone]

- Fix issue with transaction note length when a large not already exists.
When the transaction note already has maximum length (e.g. with Archetypes notes),
nothing more should be added.
Also increased the threshold back (reduced in 1.14.2).
[jone]

-------------------

- Reduce maximum transaction note length used by ftw.upgrade.
[jone]

-------------------

- Command: fix instance discover when bound to public interface.
[jone]

-------------------

- Command: add fake terminal fallback when blessed cannot be loaded.
This can happen for example when Python is built without curses support.
[jone]

- ``bin/upgrade recook`` command for recooking resources.
[jone]

- Recook resources after installing upgrades.
[jone]

- plone.reload support for upgrade step directory.
[jone]

-------------------

- ``bin/upgrade``: automatically authenticate with a tempfile
negotiation mechanism when no other authentication information is
provided.
[jone]

- New ``bin/upgrade user`` command for testing authentication.
[jone]

-------------------

- Add ``bin/upgrade`` commands ``sites``, ``list`` and ``install``.
This makes it possible to install upgrades from the console.
[jone]

- Update upgrade step scaffold to support plone.reload.
[jone]

- New JSON API implemented, accessible with `/upgrades-api`.
[jone]

- Executioner: `install_upgrades_by_api_ids` was added, allowing to install
a selection of upgrades identified by API ugprade ids.
[jone]

- Gatherer: `get_upgrades_by_api_ids` was added, returning upgrade infos
for a selection of API upgrade ids.
[jone]

- Gatherer: `get_upgrades` is deprecated and replaced by `get_profiles`.
`get_profiles` now has a `proposed_only` flag.
[jone]