Adopt commit 501105e from master: Merge pull request #698 from hversche/bsls_log_performance
Adopt commit 501105e from master: Merge pull request #698 from hversche/bsls_log_performance

commit 501105e929ec1e73f54e277f47e4e0a62ca3fd91
Merge: e989766 bbeac6c
Author: Henry Verschell <hverschell@bloomberg.net>
Date:   Fri Nov 11 13:41:13 2016 -0500

    Merge pull request #698 from hversche/bsls_log_performance

    Test severity before function call in bsls_log.  Reorganize doc.

commit bbeac6cb8c84b4e2764f0cd871a6b934905ab464
Author: Mike Verschell <hverschell@bloomberg.net>
Date:   Fri Sep 9 21:49:43 2016 -0400

    Test severit before function call in bsls_log.  Reorganize doc.

che2/bde,che2/bde,bloomberg/bde,apaprocki/bde,bloomberg/bde,apaprocki/bde,apaprocki/bde,apaprocki/bde,dharesign/bde,bloomberg/bde,che2/bde,dharesign/bde,che2/bde,dharesign/bde,bloomberg/bde,apaprocki/bde,dharesign/bde,bloomberg/bde