MFH: r393690, r393803, r393805, r393879

• Update Firefox to 40.0
• Update Firefox ESR and libxul to 38.2.0
• Phase out no longer supported LOGGING option [1]
• Temporarily disable OMTC to avoid crashes [2]

PORTREVISION was MFH'd as is to avoid merge conflicts in future.

Changes: https://www.mozilla.org/firefox/40.0/releasenotes/
Changes: https://www.mozilla.org/firefox/38.2.0/releasenotes/
PR: 202165 [1]
PR: 202174 [2]
Reported by: rsmith@xs4all.nl [1]
Reported by: many [2]
Tested by: Martin Birgmeier, Andrey Fesenko, Konstantin Belousov [2]
Approved by: ports-secteam (delphij, feld)