Tell Travis to notify Gitter with build statuses

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Remove required keyword args to support Ruby 2.0.x

This is not duplicate of #2267.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Make core bower_components requireable by plugins

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Merge pull request #2270 from opf/feature/travisci-notify-gitter
Merge branch 'release/4.0' into dev

Signed-off-by: Alex Coles <alex@alexbcoles.com>

Conflicts:
	.travis.yml
Merge pull request #2273 from marutosi/finn/release/4.0/ruby2.0

Remove required keyword args to support Ruby 2.0.x
avoid event bubling on custom field admin
Merge pull request #2283 from opf/fix/avoid_event_bubling_on_custom_field_admin

avoid event bubbling on custom field admin
moves select2 css customization to webpack
removes n+1 query for custom_values on wp#index
move some controller logic into a decorator

This is by no means clean yet, but better than it was before.
eager loading of required columns - too many for now
only load required columns
remove unnecessary block
shortens sorting
moves custom field detection to own method
refactor column handling into own method
moves methods into module
code harmonization
improve handling of desired columns