SBT 0.13.7

This allows build.sbt files without previously required blank line
separators.
http://www.scala-sbt.org/0.13/tutorial/Bare-Def.html

Closes #34387.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
sbt: add 0.13.7 bottle.
gcc: sandbox within series release number only

Fixes #33948.
Revision formulae that use gfortran for GCC bump
Revision formulae that are built against Homebrew libstdc++
gcc: update 4.9.2_1 bottle.