Translate ‘plugin not found’ phrase (octobercms#2538)

Implement support for twig macro/import

Fixes octobercms#2526

Fixes bug introduced by octobercms#2507

The many-to-many relationship types choke pretty hard on this enhancement, so only use it for the simple one-to-many/one-to-one style relations instead.
Fixes octobercms#2524

Merge pull request octobercms#2515 from LukeTowers/patch-9

Respect whitespace on disabled codeeditors

Merge pull request octobercms#2513 from gpasztor87/patch-1

Using flexbox on login and reset page.

Merge pull request octobercms#2507 from oliverpool/patch-1

Use the otherKey to update a relation

Prevent code eval on cached assets

When the request tells the server that the asset is cached, there is no point firing up the combiner, computing the contents and affecting performance. This change should result in a nice boost in secondary page load times.

Thanks to @zerkms for pointing this out

Fixes octobercms#2474

Implement button loader on demo pages

Expose isCodeViewActive API function

Recompile JS

Remove dependency for NIH method

Refs octobercms#2454