first shot on improving edit article form

(see also foodcoops#209)
update fc price dynamically in article edit form
Merge branch 'master' into article-dialog

Conflicts:
	app/assets/stylesheets/bootstrap_and_overrides.css.less
add availability to article edit dialog
remove unimplemented unit_divide box
small layout cleanup [ci skip]
update price during editing as well
make new article dialog more responsive
workaround help block margin issue [ci skip]
allow more than two columns in horizontal form
Merge pull request #218 from foodcoop-adam/article-dialog

Edit article user-interface update