picotm 0.8.0

• New transactional data structures. Picotm now supports transactional lists, multisets, queues and stacks. Operations on these data structures provide concurrency control and error detection, and integrate with the transaction manager.
• Unused functions and static variables can now be removed during the link step. This can greatly reduce the size of statically linked executables.
• Bug fix: Failure to initialize a transaction will now be handled correctly by starting error recovery. (#139)
• Bug fix: Irrevocability state is released exactly once during a roll back. (#160)