DNS record comparison should be case-insensitive

[watson]

From RFC 6762 section 10.2:

The simple rules for case-insensitivity in Unicast DNS [RFC1034] [RFC1035] also apply in Multicast DNS; that is to say, in name comparisons, the lowercase letters "a" to "z" (0x61 to 0x7A) match their uppercase equivalents "A" to "Z" (0x41 to 0x5A). Hence, if a querier issues a query for an address record with the name "myprinter.local.", then a responder having an address record with the name "MyPrinter.local." should issue a response. No other automatic equivalences should be assumed. In particular, all UTF-8 multibyte characters (codes 0x80 and higher) are compared by simple binary comparison of the raw byte values. Accented characters are not defined to be automatically equivalent to their unaccented counterparts. Where automatic equivalences are desired, this may be achieved through the use of programmatically generated CNAME records. For example, if a responder has an address record for an accented name Y, and a querier issues a query for a name X, where X is the same as Y with all the accents removed, then the responder may issue a response containing two resource records: a CNAME record "X CNAME Y", asserting that the requested name X (unaccented) is an alias for the true (accented) name Y, followed by the address record for Y.