FIX: Groups should be able to have titles longer than 50 characters (Fixes: open/5611)
Merge pull request #1334 from wilr/5611

FIX: Groups should be able to have titles longer than 50 characters
Fixed static config access in Currency and i18n (fixes #8341)
Fixed static config in BBCodeParser (fixes #8340)
FIX Clone Config_LRU incl. objects in array

Caused key confusions when using Config::nest()/unnest()
NEW Allow setting of ASSETS_DIR in _ss_environment.php
Clarified 3.1 upgrading docs
Merge pull request #1335 from chillu/pulls/config-clone-nest

FIX Clone Config_LRU incl. objects in array
Merge pull request #1336 from kinglozzer/define-assets-dir

NEW Allow setting of ASSETS_DIR in _ss_environment.php
Fixed _config.php references and usage in docs
Config docs improvement: @config and LSB mentions

Also moved some less important "notes" further down the page.
The doc is still written too much like a technical spec, we need
something that's more accessible to beginners.
Merge remote-tracking branch 'origin/3.1'
Fixed Email.admin_email config static naming
Removed unused DataExtension::$extendable_statics

Oversight from cleanup in 876f4c5
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