Add config fragment for new i18n ordering system
Simplified travis builds (external setup scripts)
composer/installers dep workaround

Moved to end of requirements, to work around a bug in composer - see https://github.com/composer/composer/issues/1147. This caused the dependencies to be installed in the wrong folder because the custom 'silverstripe-module' instructions hadn't been loaded at the time the core modules were installed via composer.
Merge remote-tracking branch 'origin/2.4' into 3.0

Conflicts:
	.travis.yml
	composer.json
Update github path
Add default params to _t() calls to ensure if a translation isn't found, it falls back to a useful English string
Merge pull request #751 from madmatt/fix_for_cms_issue_750

Fix Issue #750
Merge pull request #186 from silverstripe-rebelalliance/api/translation_priority

Add config fragment for new i18n ordering system
Updated translations
Behat: Auto-publishing SiteTree fixtures, RedirectorPage fixtures

They can be unpublished through an explicit step.
Extending from base FeatureContext in order to easily
share the same FixtureFactory but still add new blueprints to it.
Behat: Replace @database-defaults with explicit fixtures
Behat: Fixed spelling in test
More verbose fixture step definitions

Too many clashes with other steps otherwise,
e.g. with 'And the preview contains "You can fill"'.
Also removed some duplicated code no longer necessary
because we use inheritance rather than composition