Removed a TODO comment related to the 'NOTFILE all ;' statement in tools/build/v2/build-system.jam and replace with a better explanation comment. Dead code removal, Comment typo corrections. Minor stylistic changes.

[SVN r45072]

tools/build

@@ -1 +1 @@
-Subproject commit 8d75524f7f51348a94e7aefbc554c0ac798b7a61
+Subproject commit 4a702663956139e0008adcf9455c3bc5de9f3a31