[3251] Added an abstract class to handle IPv6 sockets in libdhcp++.
[3251] Implemented PktFilterInet6 class to handle IP/UDP sockets for DHCPv6
[3251] Make IfaceMgr use PktFilterInet6 object to send/recv DHCP messages.
[3251] Implemented basic tests for IfaceMgr::openSockets6.
[3251] Additional unit test for the case when there are no interfaces.
[3251] Fixed doxygen errors in the new PktFilter6 class.
[3251] Added section to developer guide about packet filters in DHCPv6.
[3251] Add control whether socket is to join multicast group.
[3251] Compilation fix for g++ 4.8.1 and gtest 1.7.0
[3251] Addressed review comments.
[3251] Merge branch 'master' into trac3251
[3243] Fix use of serial tests harness in configure.ac
[3251] Fixed IfaceMgr unit test for BSD systems.
[master] Merge branch 'trac3251'
[master] Added ChangeLog entry for #3251.
Merge branch 'trac3243_2'