Add skip for non native functions to lower false positives

[jmarcil]

Following PR #20, we have other sniffers that could benefit from suppressing issues when ParanoiaMode == 0.

Watch out to not touch things such as mysqli::query (valid equivalent of mysqli_query).

[jmarcil]

Looks like the solution from #20 and #42 could be applied to all non object based functions:

Validate if the token before is a T_OBJECT_OPERATOR and then skip it if it is.

On thing I need to put emphasis here for later: on a per bunch of function basis it's okay to remove even if paranoia is enabled, but for more broad changes I'd like it not to suppress results.