Add shutdown method for Service object (#75)

* add shutdown method

* add doc

* add test for shutdown

* use preferable pycall style

Author: HiroIshida

src/services.jl

@@ -1,5 +1,5 @@
 #API for calling/creating services. Syntax is practically identical to rospy.
-export Service, ServiceProxy, wait_for_service
+export Service, ServiceProxy, wait_for_service, shutdown
 
 """
     ServiceProxy{T}(name; kwargs...)
@@ -90,3 +90,11 @@ function wait_for_service(service::AbstractString; kwargs...)
         error("Timeout exceeded waiting for service '$service'")
     end
 end
+
+"""
+    shutdown(service_obj)
+Shut down the specified service.
+"""
+function shutdown(s::Service{ST}) where ST <: AbstractService
+    pycall(s.srv_obj.shutdown, Nothing)
+end

test/services.jl

@@ -50,6 +50,10 @@ if flag[1]
 end
 empty!(msgs)
 
+##Check the service is properly shut down
+srv_fake = Service("fake", SetBool, (req)->SetBoolResponse())
+@test shutdown(srv_fake) == nothing
+
 #Test error handling
 @test_throws ErrorException wait_for_service("fake_srv", timeout=1.0)
 @test_throws ArgumentError srvcall(SetBoolResponse())