Test system improvements w.r.t. file content matching.

    * test/BoostBuild.py (Tester.read_and_strip, Tester.expect_content):
        New methods.
    * test/test_system.html: Document the above methods.


[SVN r14274]

tools/build

@@ -1 +1 @@
-Subproject commit 3392742d1e93e5cb091bd4e1069f7fb8011bbb99
+Subproject commit a607cd9ece5b27c405fb920bdd384b884a32d412