PHPUnit & Travis failures due to new version of vfsStream.
Merge pull request #2526 from cryode/bug/vfsstream

Fix PHPUnit & Travis failures due to new version of vfsStream.
Fix Travis tests
Fixing incorect references for time zones
Merge pull request #2530 from AdwinTrave/develop

Fixing incorrect references for time zones in documentation
2.1.4 release related stuff
[ci skip] Add 2.1.4 upgrade instructions page
[ci skip] Fix 2.1.4 upgrade instructions link
[ci skip] Update download links