removed identical branches for nsign handling

Closes CID#75607
use floating-point division

Closes CID#75610, CID#75613
avoid assignments to unused variables

Close CID#75611,CID#75612,CID#75614
nicer indentation
use floating-point division

Closes. CID#75615

actually, i'm not entirely sure whether this is the correct thing to do
(e.g., do we really want floating-point division?)
modelOBJ: close FILE when returning early

to fix ressource leak.

Closes: CID#53708
removed dead code

Closes: CID#75609