Work on projects/targets.

    * project.jam: New module.
    * targets.jam: New module.
    * sequence.jam (merge): New rule.
    * os.path.jam: Bugfix.


[SVN r13402]

tools/build

@@ -1 +1 @@
-Subproject commit 5a6b39e849349d6589734480aaa516440a3f0192
+Subproject commit 5bf8f649c16b039b01aa166e0fce37faa32e7832