Remove links to images in CSG docstrings

src/ConstructiveSolidGeometry/CSG.jl

@@ -4,8 +4,6 @@
 A `CSGUnion` of two geometries `a` and `b` is defined as the set of points that are in at least 
 one of either `a` or `b` (`a || b`).
 
-![CSGUnion](../../docs/src/assets/CSGUnion.png)
-
 ## Parametric types
 * `T`: Precision type.
 * `A`: Type of geometry `a`.
@@ -64,8 +62,6 @@ UnionDictionary(g::AbstractGeometry{T}) where {T} = [Dictionary(g)]
 A `CSGIntersection` of two geometries `a` and `b` is defined as the set of points 
 that are both in `a` and in `b` (`a && b`).
 
-![CSGIntersection](../../docs/src/assets/CSGIntersection.png)
-
 ## Parametric types
 * `T`: Precision type.
 * `A`: Type of geometry `a`.
@@ -125,8 +121,6 @@ IntersectionDictionary(g::AbstractGeometry{T}) where {T} = [Dictionary(g)]
 A `CSGDifference` of two geometries `a` and `b` is defined as the set of points that are 
 in `a` but not in `b` (`a && !b`).
 
-![CSGDifference](../../docs/src/assets/CSGDifference.png)
-
 !!! note
     Note that `b` is treated as open primitive. This means that points which are in 
     `a` and on the surface of `b` will still be in the `CSGDifference` of `a` and `b`.