* ENH Make all GridField components injectable.
Some components were already injectable, but all GridField components shipped in silverstripe should be injectable.
This makes it a LOT easier to make global project-specific changes to a given component.
The new AbstractGridFieldComponent also makes it easy to make similar wide-spread changes in the future.
* DOCS Encourage injection for GridField and GridFieldComponents.
Print view uses the SilverStripe templating to render values which means that
values are safely escaped by default. This can be tested by chaing `$CellString`
to `$CellString.RAW` in the GridField_print.ss template to see this escaping
being disabled.
This pull request removes double escaping of HTML in strings.
Repairing tests and regressions
Consistently use `Security::getCurrentUser()` and `Security::setCurrentUser()`
Fix for the logout handler to properly logout, some minor wording updates
Remove the login hashes for the member when logging out.
BasicAuth to use `HTTPRequest`
Enhancement Tidy up permission icons to new icon library
WIP The modal is a short term workaround until the UI is all react based but we wanted to do some cleanup prior to 4 release
API Remove ssui.button
Enhancement Update buttons to new flat bootstrap style
