refs #6413 reduce number of jobs in travis.

Not sure if this would work. We would basically only start a job for
1 x AngualarJS
1 x JavaScript
1 x All Tests with PHP 5.4 and MySQLi
3 x All tests with PDO (5.3.3, 5.5 and 5.6)
1 x Unit test with PHP 5.4 and PDO
1 x Integration test with PHP 5.4 and PDO
1 x System test with PHP 5.4 and PDO
= 9 jobs compared to about 18 before
Merge branch 'master' into 6413_reduceTravisJobs
refs #6413 fix script error
refs #6413 do we actually need the config param? don't think so
refs #6413 remove code coverage generation for system tests.

At least for now as mentioned in ticket it does not really make sense
to run them and they take a long time > 50 minutes.
refs #6413 execute the single test suites before AllTests so we get a faster result for them
.travis.yml file is out of date, auto-updating .travis.yml file.
refs #6413 need to adjust travis template otherwise tests wont run
Merge branch '6413_reduceTravisJobs' of github.com:piwik/piwik into 6413_reduceTravisJobs
refs #6413 and again... we need to run PHP 5.4 first
refs #6413 execute js/angular tests earlier as they are quick to execute. Otherwise we have to wait forever for a result
refs #6413 wondering if this works and gives us faster test performance
refs #6413 show a message if xdebug is loaded but not needed
disable xdebug only if we have a test suite. Otherwise will be disabled when generating coverage
i think there was a semi-colon missing
.travis.yml file is out of date, auto-updating .travis.yml file.
refs #6431 and another day. Maybe it will accept my change?
Merge pull request #6457 from piwik/6413_reduceTravisJobs

Reduce the number of travis jobs from 20 to 11