Fixed columns of order items details within management.
Fixed display of amount for discounts within management.
Removed border.
Fixed calculation of discount net price within order; issue #36
Bumped version to 0.7.7.
Added field 'link' to action add form; updated docs; issue #51.
Do not remove products on manufacturer delete
Merge remote-tracking branch 'upstream/version/0.7' into version/0.7