yampa-test: Organize module Delays following Yampa's order. Refs #217.

Understanding which parts of Yampa are tested and which ones are not is
generally hard. To facilitate keeping track of which elements are tested
and which ones are not, this commit organizes the elements of Delays in
the same order and with the same haddock section separators as they have
in Yampa's counterpart.

yampa-test/tests/Test/FRP/Yampa/Delays.hs

@@ -39,7 +39,7 @@ tests = testGroup "Regression tests for FRP.Yampa.Delays"
   , testProperty "delay (small delay, qc)" prop_delay_2
   ]
 
--- * Test cases for pre and related combinators
+-- * Delays
 
 pre_t0 = testSF1 (iPre 17)
 pre_t0r =
@@ -212,6 +212,8 @@ pre_t8r = [ 0,1,1,1      -- 0s
           , 10,10        -- 12s
           ]
 
+-- * Timed delays
+
 delay_t0 = testSF1 (delay 0.0 undefined)
 delay_t0r =
   [ 0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0
@@ -268,8 +270,6 @@ delay_t5r = take 100 (drop 6 (embed sf (deltaEncode 0.1 (repeat ()))))
   where
     sf = time >>> arr (\t -> sin (2*pi*(t-0.6)))
 
--- Delaying
-
 -- | Delaying by 0.0 has no effect
 prop_delay_1 =
     forAll myStream $ evalT $ prop_always_equal sfDelayed sf
@@ -292,6 +292,8 @@ prop_delay_2 =
 
         initialValue = 17
 
+-- * Auxiliary
+
 -- prop :: SF a b -> (a -> b ->
 prop (a,b) = SP ((identity &&& a) >>^ uncurry b)