Try to upgrade cmake on Travis CI
The latest error is:
W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list.d/cmake.list:1 and /etc/apt/sources.list.d/george-edison55-cmake-3_x-trusty.list:1
I do not know where this other cmake.list
file comes from, but maybe it helps to remove cmake
from the list of packages
I've also reformatted the script
part to make the build log less confusing (it printed all commands as one multi-line string, rather than printing each command right before its output).