Include documentation

src/LabProcesses.jl

@@ -3,6 +3,7 @@ module LabProcesses
 using ControlSystems
 
 include("interface.jl")
+include("interface_documentation.jl")
 include("interface_implementations/ballandbeam.jl")
 
 include("utilities.jl")

src/interface_documentation.jl

@@ -7,13 +7,13 @@ Base abstract type for all lab processes. This should not be inherited from dire
 AbstractProcess
 
 """
-    PhysicalProcess
+    PhysicalProcess <: AbstractProcess
 Pysical processes should inherit from this abstract type.
 """
 PhysicalProcess
 
 """
-    SimulatedProcess
+    SimulatedProcess <: AbstractProcess
 Simulated processes should inherit from this abstract type.
 """
 SimulatedProcess
@@ -38,7 +38,7 @@ tuples,  `length(range) = num_outputs(P), eltype(range) = Tuple(Real, Real)`
 outputrange
 
 """
-    inputrange(P::AbstractProcess)
+    range = inputrange(P::AbstractProcess)
 Return the range of inputs (control signals) of the process. `range` is a vector of
 tuples,  `length(range) = num_inputs(P), eltype(range) = Tuple(Real, Real)`
 """