add coverall to the travis ci builds
add missing section
split the tests runs
fix path
add coverage status badge
Merge remote-tracking branch 'origin/travis-ci--with-coverage' into travis-ci--with-coverage

# By IoannisTziakos
# Via IoannisTziakos
* origin/travis-ci--with-coverage:
  fix path
append the data from the multiple coverage runs
Merge pull request #120 from enthought/travis-ci--with-coverage

Add coverall to the travis ci builds