Feature Suggestion: Add perspective size attenuation option to LineMa…

…terial (mrdoob#16912)

* Add feature to LineMaterial to support toggling screen-space line width

* Change lines parameter

* remove magic number scaling

* change if to use mix function

* build jsm

* rename variable to size attenuation, use defines

* Add perspective attenuation with width in world units

* Update comments

* Add jsm build

* revert statement position

* Change sizeAttenuation to worldUnits

* Fix endcaps not being perpendicular to line direction

* Update js examples version

* Make line look like a capsule (#6)

* update js file

* Update comments

* Add a tighter containment for capsule

* update module

* small adjustment