Remove domains

Will be reintroduced later, ideally through the use of an external 
package.

Author: HarrisonGrodin

src/ModelingToolkit.jl

@@ -10,9 +10,7 @@ abstract type Expression <: Number end
 abstract type AbstractOperation <: Expression end
 abstract type AbstractComponent <: Expression end
 abstract type AbstractSystem end
-abstract type AbstractDomain end
 
-include("domains.jl")
 include("variables.jl")
 
 Base.promote_rule(::Type{T},::Type{T2}) where {T<:Number,T2<:Expression} = Expression

src/domains.jl

@@ -4,7 +4,6 @@ using ModelingToolkit, Test
 @testset "Basic Variables and Operations" begin include("basic_variables_and_operations.jl") end
 @testset "Differentiation Test" begin include("derivatives.jl") end
 @testset "Internal Test" begin include("internal.jl") end
-@testset "Domain Test" begin include("domains.jl") end
 @testset "Simplify Test" begin include("simplify.jl") end
 @testset "Ambiguity Test" begin include("ambiguity.jl") end
 @testset "Components Test" begin include("components.jl") end