+ adding function_type to utree

+ factoring out utree i/o and adding a PP define to choose simple i/o and spirit i/o using qi and karma.

[SVN r61446]

libs/spirit

@@ -1 +1 @@
-Subproject commit 08afd8361538f4e28e83b0e22442df956b0dc993
+Subproject commit 772561f63d91b5f9cbb2f985abed02e6b7c43f41