BOOST_TEST_SYSTEM_ERROS env. variable introduced

BOOST_CPP_MAIN_CONFIRMATION renamed to BOOST_PRG_MAN_CONFIRM and twicked it's
logic a bit. It now should have value "no" to turn off pass confirmation


[SVN r16544]

libs/test

@@ -1 +1 @@
-Subproject commit 5420cce0a6e0c33d6c31a6b778f4e1c1cf7e0008
+Subproject commit 3e7d5415f99a8927381b5f1791104e3e01385c1a