Unit Tests

- Modified the test_hooks/* scripts to use /bin/sh, which is portable. When
  using /bin/bash, Cygwin and FreeBSD silently fail.

test/test_hooks/on-modify-accept

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 # The on-modify event is triggered separately for each task modified. This hook
 # script can accept/reject the modification. Processing will continue.