Instead of using the more rollup-tolerant config for all files, make the
configuration stricter by default but lower in grunt for yui modules.
This means that manual runs (prechecker) or editor integrations will
flag up the errors as well as grunt.
Also add ignore lines to the core files so that eslint isn't noisy when
not running with grunt.
There is a new theme property 'blockrendermethod' that can be set by the
theme in its config.php and tells Moodle what method it is using to render
blocks in the layout files.
Either blocks, or blocks_for_region.
Then when adding custom block regions to a page content we ensure we use
the same method the theme is using elsewhere.
This is really a hack becuase we (I) didn't properly deprecate
blocks_for_region when I added the blocks method.
Although we were previously creating the DOM markup for a block region if
it did not exist, we were not making use of it.
This change ensures that we make use of that block region as part of the
blocks code.
This change adds keyboard support to core drag and drop.
Selecting a grab handle and hitting enter (or space) will
open a menu of possible drop targets and allow you to choose one.
The only other UI change this implies is we need to show the grab
for blocks.
