Add new 'common-scanner' class, which makes writing scanners for custom

types are piece of cake.


[SVN r25086]

tools/build

@@ -1 +1 @@
-Subproject commit 54d611179508c0d9a7a543c2fb86dd5ed5d2673b
+Subproject commit 8ffe70423fba84f37da2aaadb87001a35a50ee54