i18n documentation - added note for caching in multi language modules
Style destructive actions destructively
Add backwards compatibility for has_extension
Strip duplicate querystrings from the url before adding document.location.search

When a querystring is passed with the url (for example Translatable locale) it is duplicated each time the content panel is reloaded, by adding document.location.search and so it should be stripped from the url first.
Update docblocks
FIX: Use Injector API for managing Member_Validator instance.

Updates the CMS profile page and SecurityAdmin to give developers a few ways to customise the required fields.

Added extension hook updateValidator for getValidator for things like modules to inject required fields to go along with Injector for replacing the entire class for project specific use.
Installer regression from dd49834
Merge pull request #2535 from Martimiz/3.1

Strip duplicate querystrings from the url before adding document.location.search
Merge pull request #2549 from Zauberfisch/3.1

suggest that arg_separator.output to be &
Merge pull request #2550 from Zauberfisch/3.1

formatted install.php5 according to SilverStripe coding conventions
BUG Fixed incorrect CSS class on MoneyField holder
Use quotes around composer require argument for some shells.

The asterisk is a reserved character in some shells and will cause an error
if you don't put quotes around the argument, as it will be interpreted.
Merge pull request #2555 from halkyon/readme_fixes

Use quotes around composer require argument for some shells.
BUG Fixes serious issue with FieldList::addFieldsToTab failing to accept multiple field groups.

Additional groups beyond the first are ignored.
Test cases included.
FIX oembed to avoid mixed media issues
Merge pull request #2556 from tractorcow/pulls/3.1-bug-fieldgroup-name-fix

BUG Fixes serious issue with FieldList::addFieldsToTab failing to accept multiple field groups.
Merge pull request #2554 from tractorcow/pulls/3.1-moneyfield-style-fix

BUG Fixed incorrect CSS class on MoneyField holder
HTML attr encoding for UploadField config

Also fixed UploadField operation with canUpload=false,
which broke the JS because no config could be found,
since the <input> field wasn't present. We can't put the data-config
attribute on the field holder, since fields can be rendered
without their field holder through FormField->SmalLFieldHolder().

Fixes https://github.com/silverstripe/silverstripe-cms/issues/874
FIX Changing `public` static `$priority` to `private`

Deprecation error thrown in master whilst this is public
Merge pull request #2539 from dhensby/patch-2

FIX Changing `public` statics to `private`