Adds a couple of usability tweaks to the dropdown cell type in the data table widget, to more closely mimic a native dropdown field.
Pressing the up or down arrow keys when the cell is focused but with the dropdown closed will select the previous or next item automatically and set it as the cell value. This does prevent the usual table function of going to the previous or next row when focused on a dropdown cell, but I think it's a worthwhile trade-off. When the dropdown is open, the up and down arrows work the same as previously implemented.
Typing out characters will initiate a search and select the first matching option automatically and set it as the cell value. For example, for the following options:
Apples
Oranges
Bananas
Typing out o and r on the keyboard will automatically select the Oranges option.
Credit to @bennothommo
Credit to @tobias-kuendig. Added $.oc.relationBehavior.changed function. To keep track of changes made using the relation controller this new "changed" function is called every time a record is created, added, removed or deleted. The function triggers the change.oc.formwidget event on the form field that belongs to this relation controller so other form fields are notified about the changes.
Credit to @Farrow. Previously when creating a backend form with RainLab.Builder if you filled in the "Default" property using the i18n (to get, for example, acme.plugin::lang.field.default) then that string would be output exactly on the form (i.e. <input value="acme.plugin::lang.field.default"...>) instead of being replaced with the actual value of that key from the lang file.
This enables developers to modify what the cache key is for a given instance of a settings model so that they can do things like load user dependent settings values and have those values affect the rendered CSS. Previously the key being static across all instances of a given setting model would prevent that from being feasible without clearing the cache for every request.
Replaced the existing PNG flag icons with the flag-icon-css library that uses SVGs, has more flags, and is more active (i.e well maintained). Credit to @mariavilaro & @w20k. Thanks to @petehalverson for Octodock for easy testing of this.
The removed css rule makes filelist entries unreadable on touchscreen clients
that also have default pointer input support. The entries have a blue background
with white text when hovered. By setting the background to transparent the
text is no longer readable. Credit to @tobias-kuendig
