Generic traceback handling in python.

Conflicts:
	src/bin/memmgr/memmgr.py.in

The UNHANDLED_EXCEPTION is renamed to PYTHON_UNHANDLED_EXCEPTION,
because only python code produces this one.

Conflicts:
	ChangeLog

 - LeaseType is now initalized from static array
 - @todos added in 2 MySQL tests
 - Added a comment about lease type values to MySQL schema

Conflicts:
	ChangeLog

* Fix the unittest so that it compares the correct object (tsig6)
* Store canonical long-form HMAC name in case of HMAC-MD5
  + Update TSIG RDATA class (test already present)
  + Update TSIGKey class (new tests added)

Using EXPECT_EQ on class D2Dhcid failed under gtest 1.5
due to lack of "<<" operator.  Adding it solves this problem.

Adds the initial implementation of b10-dhcp-ddns NameChangeTransaction class.
This class is an abstract, state-model driven class which provides the basic
mechanics for performing DDNS updates based on a NameChangeRequest.

This initializes the basic data structures of the memory manager and
starts loading data into the segments.