properly crash runner_task in tests. tests for async_map

test/async.jl

@@ -0,0 +1,17 @@
+
+facts("Async") do
+
+    context("async_map") do
+        x = Input(1)
+        t, y = async_map(-, 0, x)
+
+        @fact value(t) --> nothing
+        @fact value(y) --> 0
+
+        push!(x, 2)
+        step()
+        step()
+
+        @fact value(y) --> -2
+    end
+end

test/runtests.jl

@@ -2,7 +2,7 @@ using Reactive
 
 # Stop the runner task
 try
-    throwto(Reactive.runner_task, InterruptException())
+    Base.throwto(Reactive.runner_task, InterruptException())
 catch
 end
 
@@ -11,4 +11,5 @@ include("basics.jl")
 include("call_count.jl")
 include("flatten.jl")
 include("time.jl")
+include("async.jl")
 FactCheck.exitstatus()