improved error message when exporting code from MATLAB interface
Update .travis.yml

Added clang compiler to the test script
Update .travis.yml

Added notifications "hook" -- send an email in case of failure
minor warning related to exported file integrator.c for ERK methods fixed #32
Merge branch 'master' of github.com:acado/acado
Fixed warning in the plotting module; Working on #32
Merge branch 'master' of github.com:acado/acado