Sundry improvements:

    Bison and lex support.
    unit-test rule
    --version option
    default build really works

    * new/build-system.jam: Bugfixes. Added "--version" option.

    * new/project.jam: If default-build is not specifies, don't stick "debug".

    * new/property.jam (evaluate-conditionals): New rule.

    * new/targets.jam (basic-target.generate): Evalute conditional properties.

    * test/BoostBuild.py (Tester.maybe_do_diff): New method.
        (Tester.run_build_system): Call the above method when
        appropriate.


[SVN r15771]

tools/build

@@ -1 +1 @@
-Subproject commit 4b5d5cc6e4a500c522e8e03a4e95d546301034d1
+Subproject commit 4115276dec781ead96d146da4d8bb7da90c00fe9