Added variable initializing to limit error_log messages

Running nuBuilder application the error.log file size is increasing rapidly, the most due to bad or missing variable initializing.
The most significant changes are in nucommon.php file, as this is often invoked.

This commit solves most of the issues:
https://github.com/massiws/nuBuilderPro/commit/d2b81249fd844a7efb09995a7a68e5d029312a74