[PrefabMaker] fix for duplicated objects

+ whenever there were 2 objects with exactly the same name, attached to
the same bone, but with different Z-order, the one that was added first
was deciding on ordering
+ currently a warning is issued and it is assumed that the one closest
to the screen is the proper one (lower Z index)

! this doesn’t solve balance_check animation problem entirely as there
is a problem with changing Z-index for a single frame
[CurveCalc] pre-cleanup

+ assert in place of exit, to show call stack
+ comment to the ugly code
[AnimationClip] ugly bugfix

+ whenever an object was skipped, it’s Z-sort position wasn’t taken
into account
+ ugly fix places None x and y positions along with z and places them
in curves calculator
+ curves calculator goes through whole given data and fills Nones using
linear interpolation

! this is as ugly and hacky as it gets. it have to be rewritten soon as
this code is less and less readable
[AnimationClip] removing final object disappearance

+ no final key is generated for object enable
[CurveCalc] ugly hack part 2

+ filling missing values at the end of the dictionaries
[CurveCalc] removing logs
[AnimationClip] ugly hack for scale and rotation

+ the same hack that i’ve used for position was applied to rotation and
scale

! this broke “Pickups” from essential pack
[AnimationClip] removing hack for scales

+ this is weird - scales just break for Pickups, didn’t notice it for
platformer pack character :/

! this code grew so ugly that a refactor is required