Add separate npm Karma script, invoked by npm test

Signed-off-by: Alex Coles <alex@alexbcoles.com>
use private sprockets fork

The sprockets maintainer yanked the sprockets version we
use from rubygems. It happened that I had the specific sprockets version
at my harddrive.

We really should update sprockets, but until this happens, the fork can
be used.
Merge pull request #2130 from opf/hotfix/yanked_sprockets

use private sprockets fork
Merge pull request #2113 from opf/fix/add-npm-run-karma

Add separate npm Karma script, invoked by npm test
Add packager installation guide

Also moved manual installtation guide to operation_guides
to be more flexible which kind of documentation will be
placed into this folder.
Minor changes of style
Merge pull request #2131 from opf/hotfix/packager_installation_guide

Add packager installation guide.
Merge branch 'release/4.0' into merge/release4.0_into_dev

Conflicts:
	package.json
Merge pull request #2132 from opf/merge/release4.0_into_dev

Merge release4.0 into dev