Set the Composer minimum-stability key to "dev" until we're in RC
Add prefer-stable to extension composer.json

Signed-off-by: Gawain Lynch <gawain.lynch@gmail.com>
Merge pull request #1737 from GawainLynch/hotfix/composer-pre-rc-minimum-stability

Set the Composer minimum-stability key to "dev" until we're in RC
git push origin masterMerge branch 'sbonardt-feature/issue-1730-backend-IE8'
Merge branch 'master' of github.com:bolt/bolt
Disable UI elements when extensions cannot be managed in backend

It's not perfect, but it'll have to do.
Add meta tag "X-UA-Compatible" for IE.
Don't do this on IE8. Working on #1730.
Wrap Select2, to make it work in IE8. Working on #1730.
fix to double initialisation bug
Merge pull request #1742 from rossriley/extensions-improvements-fixes

Cheers @bobdenotter and @rossriley 

Fixes #1739
Merge remote-tracking branch 'upstream/master' into feature/issue-1730-backend-IE8