[feladat @ 270]
Added validation for SRV records. Closes #45. Updated validation for TXT records to allow for DKIM. Closes #49. Renamed is_valid_mx_or_ns_target function to more generic name is_valid_non_alias_target.
(^|/)\.svn($|/)
(^|/)\.hg($|/)
(^|/)\.hgtags($|/)