Adjust Travis build file
Adjust Travis build file

- Remove not needed debug messages (also print by CMake)
- Add gcc-6 to packages
- Remove the "compiler" entry because it has overwritten "g++-6" (Build
Job 1):

Setting environment variables from .travis.yml
$ export COMPILER_NAME=gcc
$ export CXX=g++-6
$ export CC=gcc-6
...
$ export CXX=g++
$ export CC=gcc

lorenzhaas/cppcrate