Option to block/not forward all AAAA queries

[DL6ER]

This adds an option to limit regular expressions to specific query types:

RegEx engine improvements

New feature: Apply regex only to a specific query type. Example: abc;querytype=AAAA will block dig AAAA abc but not dig A abc This is still experimental. Tests would be appreciated.

You could try this with an regex + query type AAAA:

;querytype=AAAA

Note that this is still an experimental feature and may not fully work under all circumstances. However, I'm thankful for reports if something doesn't work.