The PR fixes an error in .travis.yml that was not checking for errors in examples/run_examples.sh correctly, so any errors in the examples files were not being caught.

Details: the original code used a command of the form

if [condition]
    cd examples; bash run_examples.sh; cd ..
fi

The if command returns the status of the last command, which in this case is cd .., which is always true. The fix uses the construct

if [condition]
    (cd examples; bash run_examples.sh);
fi

which still leaves the script in the main directory but returns the exit status of the bash command.