Make TestCase::hasOutput() return true if "0" is outputted

TestCase::hasOutput() returns false when "0" is outputted, as it uses empty(), which returns false on the string "0".
Merge pull request #922 from dave1010/3.7
Revert "Sync with 19f1d74."

This reverts commit f3dc675fbc6670ed6335f898efd07a4b25f04697.
Revert "Sync with API change in PHP_CodeCoverage 1.2.10"

This reverts commit 19f1d742e0c36150001062f592c93f80aef3a9fd.
Upgrade PHP_CodeCoverage
Prepare release
Fixes #573, Fixes #552, Fixes #582.

[BC BREAK]

All relative paths in a configuration file are now resolved relative to that
configuration file. When upgrading, you may need to update relative paths for
the following configurations:

 * `testSuiteLoaderFile`
 * `printerFile`
 * `testsuites/file`
 * `testsuites/exclude`
Merge branch '3.7'
Revert "Revert "Sync with API change in PHP_CodeCoverage 1.2.10""

This reverts commit fdf112c62f9a882f1c66ead6576eb011013d081a.
Updated path resolution for symlinks

I wanted to symlink the file in vendor/bin to an other folder and `__DIR__` was resolved to this new folder.

by adding `realpath` it resolves the symlink and works again.
Merge pull request #932 from onigoetz/patch-1
Revert "Merge pull request #932 from onigoetz/patch-1"

This reverts commit 12a391c9d824f0eaebe577429ad20ab86e792d44, reversing
changes made to 439f7f6de0cb5b04c4cf160fdd02b59964d49a08.
Improved support for asserting on traversable objects.

 * Assertions using `PHPUnit_Framework_Constraint_Count` now support traversable objects.
 * Assertions using `PHPUnit_Framework_Constraint_TraversableContains` now give messages that mention the `Traversable` interface.
Fix
Upgrade PHPUnit_Selenium
Fix
Upgrade PHPUnit_Selenium
Sync 89b9c5d.
Give PHP 5.5 on Travis CI another try
Add dependency