instantiate all distributions with float, double, and long double

don't use rand48 unless it's available
(Michael Stevens)


[SVN r15952]

libs/random

@@ -1 +1 @@
-Subproject commit 839f42d50f00d258f6233854c31c770cebf3625e
+Subproject commit 2ba0e22f9b5ba8f727b4ff59eea1801ead2dc6ec