patch 7.4.2180

Problem:    There is no easy way to stop all timers.  There is no way to
            temporary pause a timer.
Solution:   Add timer_stopall() and timer_pause().

src/testdir/shared.vim

@@ -109,14 +109,17 @@ func s:kill_server(cmd)
 endfunc
 
 " Wait for up to a second for "expr" to become true.
+" Return time slept in milliseconds.
 func WaitFor(expr)
+  let slept = 0
   for i in range(100)
     try
       if eval(a:expr)
-	return
+	return slept
       endif
     catch
     endtry
+    let slept += 10
     sleep 10m
   endfor
 endfunc