BUGFIX Versioned_Version->relField() so fields can be used in GridField etc

Copied from DataObject, since we can't use the $fallback opion in this case
(will try to retrieve from wrong class)
Deprecation docs
Removed internal/outdated/speculative docs from requirements.md
Merge pull request #1312 from chillu/pulls/deprecation-docs

Deprecation docs
NEW: Move temp data into a user-specific subfolder, to stop temp-permission bugs from occurring.

Anyone who has run "sudo -u www-data ./framework/sake dev/build" knows that SilverStripe's temp
folder permissions can be very brittle.  This patch resolves this by making the temp folder
user-specific.

To minimise directory pollution it first creates a chmod 777 parent folder with the same name
as the current folder.  It then creates a subfolder of this with the same name as the current
user.

The positive impact of this change is that sake can be used without fear of messing up file
permissions.  This means, among other things, that we can put a Composer post-update-cmd into
the installer to run dev/build.  Progress!

The negative impact is that you will get two caches if you run sake as a different user.  However,
that is much better than the current situation - which is a bunch of bugs - and if you're concerned
about that, you still have the option of running sake as www-data.
Fixed path in docs
FIX Unset internal metadata on TreeDropdownField setValue()

Otherwise the hidden field value and metadata will get out of sync.
Most commonly used together with setTitle('') as well.
FIX Don't silently unset ParentID in "add page" dialog

Happened when changing the page type, because the "selectedNode"
property isn't set in all cases
API Make Object::config use late static binding

Can now be used in instance scope, like:
  $this->config()->db
and in static scope, like:
  Page::config()->db
BUGFIX: fixed access to asset_preview_width in getFieldsForImage
Merge pull request #1341 from g4b0/8347-getFieldsForImage

BUGFIX: fixed access to asset_preview_width in getFieldsForImage
API i18n::$common_languages and i18n::$common_locales converted to Config API

They are now accessed via the Config API, and contain associative rather than indexed arrays.
Before: `array('de_DE' => array('German', 'Deutsch'))`, after: `array('de_DE' => array('name' => 'German', 'native' => 'Deutsch'))`.

Also fixed a i18n.js_i18n config accessor
Fixed help_link config usage
Remove incorrectly added diff file
Fixed i18n.common_locales definitions
Solved json obj to array issue
Merge pull request #1344 from g4b0/8330-cache-issue-in-CMSVersion

Solved json obj to array issue
FIX: Set ModelAdmin tab targets to avoid creating new panels
Merge pull request #1345 from ajshort/pulls/modeladmin-tabs

FIX: Set ModelAdmin tab targets to avoid creating new panels
Include padding on padded edit form panels inside a tabset