Add phplinting for two versions of PHP
Make the lint run on lowest and highest tested php versions
Limit linting to php files and run lint in parallel sessions for speed
Let's try that again with a colon at the end
fi
Let's run the phpcs selectively as well then
Update the environments

- The WP.org git repo does not have minor version branches, only major versions
- The WP.org git repo master is currently 4.0-beta3, so we should test v 3.9(.4) separately
Mix the environments up a bit better
Merge pull request #1392 from jrfnl/Travis-php-lint

Add phplinting for two versions of PHP and run PHPCS only once per build.