- Major modification to the RPC messaging architecture to fully embrace
 thread-local buffers. Slightly slower per call. But much much more parallel.
 - Synchronous engine modified to use fibers.
 - To support that a fiber_barrier and a fiber_conditional had to be
 built
- Missed files in the previous checkin
- Added support for multiple buffers in the thread-local buffer to
avoid calls to realloc
Modified receiving strategy to decrease the number of calls needed to receive
Error in the push_flush implementation of the thread_local_send_buffer
 - RPC Request performance improvements: to use a more aggresive flush.
 - Reduced length of lock when extracting buffers from the thread local send buffer
Added more fine grained locks to the thread local buffer to improve parallel performance under high contention.
 - Fixed silly error in thread_local_send_buffer where a buffer is modified twice, once onsafely.
 - simplification and performance improvement of dc_buffered_stream_send
Added a barrier to the DHT performance test for reliability.
Improved buffered exchange performance slightly by ensuring more consistent flushing.
RPC:
 - Deleted some unused POD_CALL stuff.
 - Centralized all the compile time options in dc_compile_parameters.hpp
Merge branch 'master' of github.com:ylow/graphlab
Erroneous documentation for one of the parameters. SEND_POLL_TIMEOUT is in microseconds not nanoseconds
 - Added a fiber_control::fast_yield to only consider yields within the same affinity group
 - exchange now calls yield.
More major performance improvments by removing the last locks from the thread local buffers.
Tweaked the buffered exchange buffer control to match the new buffering model in RPC better.
Minor modification. Split calls may now interleave arbitrarily with any calls
occuring between split_call_begin and split_call_end
 - Reverted the last change where split calls may be arbitrarily interleaved.
Now split calls are temporally ordered when split_call_end is called.
 - Added a fiber_aware buffered exchange
Changed a compile parameter in RPC.
 - This breaks serialization backward compatibility!
 - Uses variable length encoding for unsigned long serialization. This
 can decrease header size quite dramatically resulting in large performance
 gains for asynchronous methods.
Made fiber_barrier assignment operator private
Changed default number of fibers from 3000 to 10000.