Use a preprocessor sequence for the primes.

This feels like overkill but it seems to be the most reliable way to ensure
that the length is correct. I obviously can't be trusted to get it right, and
the template hack seems to prevent Boost.Range from working.

[SVN r52711]

libs/unordered

@@ -1 +1 @@
-Subproject commit ce379f7bb555ebf266d70d9d10e561219bcfc0aa
+Subproject commit 3e70155100b1f69c66e6413d9204f598034925df