BIND 10 #2432: define and implement base and libdns++ version of RRsetCollection

[BIND 10 Development]

#2432: define and implement base and libdns++ version of RRsetCollection
-------------------------------------+-------------------------------------
            Reporter:  jinmei        |                        Owner:
                Type:  task          |  UnAssigned
            Priority:  medium        |                       Status:
           Component:  libdns++      |  reviewing
            Keywords:                |                    Milestone:
           Sensitive:  0             |  Sprint-20130108
         Sub-Project:  DNS           |                   Resolution:
Estimated Difficulty:  5             |                 CVSS Scoring:
         Total Hours:  0             |              Defect Severity:  N/A
                                     |  Feature Depending on Ticket:
                                     |  loadzone-ng
                                     |          Add Hours to Ticket:  0
                                     |                    Internal?:  0
-------------------------------------+-------------------------------------
Changes (by muks):

 * owner:  muks => UnAssigned
 * status:  assigned => reviewing


Comment:

 Up for review.

 * The documentation can be improved I think. Please point out if it is
 insufficient.
 * Note that the `RRsetCollection` implementation's constructor takes
 origin and class arguments. These are required by the master loader. OTOH,
 `find()`'s `RRClass` is unused as the loader loads records for just a
 single class. In any case, this is specific to the libdns++ implementation
 and will be unused within datasrc I think.
 * I had to do a lot of `shared_ptr` magic for iterator copying to work
 (esp. for the postfix ++ operator). If there is a simpler way of doing
 this for the virtual implementation, let me know in the review.

 I don't think this requires a `ChangeLog` either.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2432#comment:6>
BIND 10 Development <http://bind10.isc.org>
BIND 10 Development