Revert "Revert "Merge pull request #1478 from opf/feature/with-angular-busy""

This reverts commit afe276384e07def25b3a8ddb0d8ffd0a3a1ef248.
Fix IE11 trouble with ``disabled`` attribute


Remark: Assumingly ``ng-attr-disabled`` would be another valid work around
Correctly add angular-busy css to asset path
Merge branch 'dev' into fix/IE11-trouble-with-spinner-branch

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

Conflicts:
	public/templates/work_packages.list.html
Merge branch 'fix/IE11-trouble-with-spinner-branch' into dev