print.jam; support use of "::" as prefix in paragraphs/blocks to output preformatted text.

class.jam; add use of "::" for code samples.


[SVN r16019]

tools/build

@@ -1 +1 @@
-Subproject commit fc1b00f0013a85eaa0cb900849963af4c232ade6
+Subproject commit 191011169351bf716f402965b69ef7309ca8bf4f