Revert gcc min to 4.8.

I was a bit overzealous in my upgrade to 4.9, and based it solely on
distr default versions. But after more thorough checking, C++11 is
pretty much complete with gcc4.8.
And besides, Amazon Linux Devloper Toolset on Amazon Elastic Could for
now offers 4.8 as default.

.travis.yml

@@ -27,7 +27,7 @@ addons:
       - sourceline: 'ppa:duggan/bats'
     packages:
       - valgrind
-      - g++-4.9
+      - g++-4.8
       - bats
 
 #env:
@@ -57,7 +57,7 @@ notifications:
 
 install:
   # Build SimulationCraft
-  - if [ "$TRAVIS_OS_NAME" == "linux" ]; then CXX=g++-4.9 && ${CXX} -v && make CXX=g++-4.9 DEBUG=1 -C engine -j 2; fi
+  - if [ "$TRAVIS_OS_NAME" == "linux" ]; then make CXX=g++-4.8 DEBUG=1 -C engine -j 2; fi
   - if [ "$TRAVIS_OS_NAME" == "osx"   ]; then make DEBUG=1 SANITIZE=1 -C engine -j 2; fi
 
 script:

engine/config.hpp

@@ -63,13 +63,14 @@
 #  error "Visual Studio 11 ( 2012 ) or lower not supported"
 #endif
 
-// Last updated 2017-11-06: Support Debian 8 (Jessie) with gcc 4.9 and clang3.5
+// Last updated 2017-11-07: Support gcc4.8 with full C++11 support for now
+// Debian 8 (Jessie) with gcc 4.9 and clang3.5
 // Ubuntu 16.04: gcc 5.3, clang3.8
 #if defined( SC_CLANG ) && SC_CLANG < 30500
 #  error "clang++ below version 3.5 not supported"
 #endif
-#if defined( SC_GCC ) && SC_GCC < 40900
-#  error "g++ below version 4.9 not supported"
+#if defined( SC_GCC ) && SC_GCC < 40800
+#  error "g++ below version 4.8 not supported"
 #endif
 
 // ==========================================================================