issue504: verbose output displays node IDs for each test

Replace the verbose per-test reporting format of `file:line test_name RESULT`
with the node ID of the test, i.e. `file@line::class::method[param] RESULT`.

This patch does not update the examples in the docs; @hpk42 has a script
to regenerate those.

--HG--
branch : issue504

CHANGELOG

@@ -1,6 +1,10 @@
 NEXT (2.6)
 -----------------------------------
 
+- change -v output to include full node IDs of tests.  Users can copy
+  a node ID from a test run, including line number, and use it as a
+  positional argument in order to run only a single test.
+
 - change XPASS colour to yellow rather then red when tests are run
   with -v.