Add existing sniffs to check for validation/sanitization of all input, escaping of all output.
Add existing sniffs to check for validation/sanitization of all input, escaping of all output.

Lowered the error level to warning for both.

Fixes #37

WPTRT/WordPress-Coding-Standards,WPTRT/WordPress-Coding-Standards,WPTRT/WordPress-Coding-Standards,WPTRT/WordPress-Coding-Standards,WPTRT/WordPress-Coding-Standards