DZ Items + Weapons correction

building crate:
Added - Gun Rack Kit, Scaffolding Kit and Round Bag Fence
weapons crate:
Fixed to DZ version - AS50, DMR, Crossbow, M107, M240, M249, M60 and
Pecheneg.
skinChange - Undeclared+Unused variable

Code cleanup and fixes:
- fixed local declaration.
- array for backpack types.
- simplified matching routine
- unused+undeclared _i variable (index; removed).
fixed with the "magic variable" *_forEachIndex* that holds the array
index to each element.
skinChange - added backpack check

Added routine check for the backpack.
If _palyer doesn't have one, no need to go through the removal/add of
the backpack.
Merge Conflict fix

rebasing forked repo