* 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.
Forcing sort by the first search field isn't always appropriate.
When a custom search list is used, we can set the expectation that custom sorting is intended as well.
As an example, this can be used to autocomplete based on FULLTEXT indexes,
and sort based on relevancy.
Enhancement add accessibility info to page number
Enhancement new font icons added, improve trash icon and increase icon size of close
Enhancement improve title of gridfield search trigger
Enhancement add title to button to open gridfield search and improve gridfield search styles
API Shortcode fails if no parent
API JQuery-UI classes removed
Enhancement centre actions tabs within dropup in more-actions
Enhancement fix IE input height issue and fix for safari of icons in buttons with hidden text (e.g. pagination)
Enhancement only show external link on hover