* FEATURE: Added aggregate filter instance support
* FEATURE: Added record filter instance support
* FEATURE: Added Threader and Base_Thread, which offer first class support for MADARA-enabled threads
* FEATURE: Added a thread-safe refcounter class and updated Knowledge_Base to use it for counting Thread_Safe_Context between threads.
* FEATURE PARTIAL: Reliable_Record skeleton added for future reliable fragmentation and acknowledgment tracking of data.
* FEATURE PARTIAL: Work_Units have been added. Another class similar to Threader for Work Units will be needed to take advantage of it. Work_Unit will allow for schedulable, period executions within a thread.
* TESTS: Added tests for threader and reliable record
* Updated version to 1.9.12

git-svn-id: http://madara.googlecode.com/svn/trunk@1404 2850746a-f1c8-11dd-b507-8b4ecd5210be