better docs
Merge branch 'master' of github.com:miekg/dns
Disable the unfinished CAA support

CAA was partially implemented, it's better to do it 100% until that
time handle CAA as an unknown record.

Closes #70:
Merge branch 'master' of github.com:miekg/dns
Add todo
Correct doc
Cleanup singleFlight a bit
Remove stale comments
Introduce msg.PackBuffer() - it's like msg.Pack() but can reuse a byte buffer

msg.Pack() always allocates a byte slice. This is good for simplicity,
but in a serious application it's preferable to reuse byte slices to
reduce the GC overhead. This patch introduces a new public method:
PackBuffer(). It's exaclty like Pack() but is able to reuse a
given byte slice. It will still allocate a new slice if the given one
is too small.
msg.Copy() makes a deep-copy of the msg object

There was a copy function that did shallow copies of the msg
object. Export it and make it support proper deep copying.
Fix single-entry TXT parse length test
Define length in multi-entry TXT parse length test in terms of header + rrdata
Test parsing of TXT records containing empty-strings
Fix parsing of TXT records containing empty-strings
Merge pull request #75 from andrewtj/atj-txtparsefix

Fix parsing TXT records containing empty strings
Also add empty txt record in another test
Add test for RRSIG with timestamp in epoch

This is standard's compliant but currently not supported.
RRSIGs: parse epoch timestamp too

According to RFC4034 the timestamp in RRSIG may also be an EPOCH.
Check for this when parsing. Knot DNS zone dumps contain timestamp
RRSIG, this makes those parseable by Go DNS.
add test for matching text records
Add quoteString function.

This is to just quote a string s -> "s"