Merge pull request #20 from kenguest/master

Check/cache value before using it in  to avoid index not set errors (that are logged to system.log file).
Use getenv() instead of $_ENV

https://github.com/classyllama/Wiz/issues/22

getenv() doesn't require E activated in variables_order, though will work from scratch on every server without it activated
Merge pull request #23 from grimmlink/patch-1

Use getenv() instead of $_ENV
Merge remote-tracking branch 'upstream/master'