Travis integration

- The include path is changed so we can make sure we don't use the system installed phpunit files by accident. Hopefully process isolation doesn't break this
- The pear-core dependency is for PEAR_RunTest that can't be pulled in with composer as it's not a pear package but pear core
- pear console-getopt is a dep of pear-core
- --prefer-source is used to avoid issues with github api limits when downloading the zips.
- The one skipped test doesn't work on travis and I'm not sure why and I'm aware this is not the nicest way to skip it but using $_ENV doesn't work due to the way the .phpt tests are executed